Xenserver Has Terminated the Upload of the Virtual Disk

April 12, 2022 Post a Comment

The Dell EqualLogic PS5000E line spans from ii to sixteen TB in capacity in a single assortment, utilizing SATA drives

ranging from 250GB to 1TB. The PS5000X arrays offer six.4TB or raw storage chapters utilizing 400GB,

ten,000 RPM Series Attached SCSI (SAS) disk drives. The PS5000XV arrays use 146GB or 300GB 15,000

RPM Serial Fastened SCSI (SAS) disk drives to deliver ii.3TB or 4.8TB of raw capacity, respectively. The

PS5500E assortment utilizes 48 7200 RPM 500GB or 1TB SATAII drives to deliver 24 or 48 TB of raw capacity

in a 4U enclosure.

Performance and capacity may easily be scaled by adding additional PS Series arrays. All PS Serial

models have dual controllers with 3 1GbE ports per controller, for a total of six 1GbE ports.

XenServer five.0 Dell Edition

overview

With the 64-bit open up-source Xen hypervisor at its core, Citrix ® XenServer ™ Dell Edition is a powerful

virtualization solution that enables efficient resource consolidation, utilization, dynamic provisioning, high

availability and integrated systems management. XenServer Dell Edition has a small foot print and is

optimized to run from an internal flash storage in Dell PowerEdge ™ servers. Dell and Citrix have partnered

to bring pre-qualified and virtualization-ready platforms for today'due south dynamic and growing data centers.

What's new in XenServer five.0 Dell Edition?

Expanded hardware and systems management back up

Expanded Server Support —XenServer 5.0 is now supported on an expanded list of Dell PowerEdge

servers. PowerEdge 1950 III, 2900III, 2950III, R805, R900, R905, M805 and M905 are now fully qualified

and supported to run XenServer 5.0.

Expanded Storage Support —Storage arrays supported by Dell with XenServer 5.0 include

Dell PowerVault ™ MD1000, MD1120, MD3000, MD3000i and Dell EqualLogic PS5000 arrays.

XenServer 5.0 also includes a new Dell EqualLogic PS Serial Storage Adapter that not only simplifies

virtual machine storage management, but also enables advanced PS Series features to exist used past

XenServer hosts.

OpenManage 5.5 —With Dell OpenManage ™ 5.5 integrated in XenServer 5.0, customers can easily

monitor and manage server hardware and straight attached storage from a unproblematic to apply web user

interface or CLI. Dell Remote Access Controller (DRAC) five provides out of ring, including full KVM

and virtual media, access to the server.

Faster and more powerful

machines, with more users and faster applications onto Dell's 64-bit PowerEdge servers. The Xen ® 3.two

hypervisor includes control domain performance tuning, updated paravirtualization drivers and VHD

functioning tuning.

Tuned for Windows —XenServer adds back up for Windows Server 2008, has been optimized to run

Windows-based workloads and has been certified on both 32-bit and 64-flake versions of Windows

Server through Microsoft's Server Virtualization Validation Plan (SVVP).

Tuned for XenApp —Citrix XenApp ™ users benefit from XenServer'due south memory management

functioning enhancements for XenApp workloads. More users and faster applications pb to more than

efficient application delivery with XenApp.

half-dozen

Simplified direction

Usability enhancements —XenServer v.0 includes 30 new ease-of-use enhancements to make it

simpler for customers to use the XenServer platform.

Search, sort and tag —The XenCenter ™ management console allows administrators to tag and

search virtual infrastructure with ease to keep track of virtual machines as they proliferate beyond

large datacenters. Web 2.0 style tagging and searching capabilities allow It professionals to assign

metadata and virtual tags to workloads, either pre-defined or customized to each organization's needs.

Performance monitoring and alerts —XenCenter includes performance monitoring, trending and

alerting. Hands rail primal operation statistics for virtual and concrete servers to identify hot spots,

residual computing resources and warning administrators about potentially detrimental server behavior

or changes.

Wizard driven —XenServer includes new Wizard-driven utilities such equally XenConvert which transforms

concrete servers into virtual machines in minutes. The XenCenter management console also includes

new wizards for advanced storage and server networking configurations.

Disaster proof

Automated loftier availability —XenServer adds automated loftier availability (HA) with resource-based

placement of virtual machines in the event of server failures. Automated HA includes dynamic

fail-over planning based on available resource to assistance ensure that virtual machines always restart

on the appropriate physical server.

XenCenter self-healing —XenCenter combines new automated HA with its distributed management

compages to create a self-healing, hard to kill management panel. Every server in a resources puddle

can exist a fail-over target for the XenCenter management console.

Disaster recovery —XenServer includes enhanced back up for SAN based remote replication and

auto-backup of virtual machine configuration to remote sites.

The only dynamic provisioning game in town

Windows Server 2008 and Hyper-5 support —XenServer now includes the ability to stream

Windows Server 2008 workloads to physical servers or even Hyper-V (and associated workloads)

to blank metal servers for dynamic provisioning of server workloads.

Additional Microsoft integration —Role based administration using Active Directory, virtual hd

(VHD) compatibility and out-of-the-box integration with Microsoft SQL Server are just a few of the many

Microsoft related enhancements in XenServer'due south dynamic provisioning capabilities.

EqualLogic PS Serial and

XenServer

Dell EqualLogic PS Serial iSCSI arrays simplify storage deployment past offering high performance,

reliability, intelligent automation, and seamless virtualization of a single puddle of storage. A PS Series

SAN provides intelligent automation of storage management as well as virtualized storage assets. With

unmarried panel management and ease of storage provisioning, an EqualLogic PS Series SAN increases

the power and flexibility of a virtual infrastructure. The arrays present a single virtualized pool of storage

resources to attached servers. Additional arrays tin be seamlessly added into an existing SAN to

automatically increase storage pool resource without disruption of application or information availability.

Dell EqualLogic storage brings unique benefits to the Citrix XenServer virtualization solution.

Optimized utilization

While XenServer provides an fantabulous virtualization platform to consolidate and optimize server

resource usage, EqualLogic PS Series storage arrays optimize storage utilization by dynamically

balancing loads amid multiple storage arrays as the usage changes. Additionally one tin can configure

thin-provisioned volumes to abound on-demand only when additional storage is needed for those

volumes. Thin-provisioning can increment the efficiency with which the storage resource are utilized.

The XenServer EqualLogic Storage Adapter allows sparse volumes to be created from the XenCenter

interface or using XenServer CLI, thus optimizing storage requirement and simplifying storage

deployment for virtual machines.

Reduced deployment time and effort

EqualLogic PS Series arrays reduce the time and effort required to deploy a SAN. Inside the

EqualLogic PS Series Grouping Manager, one tin hands create new volumes and assign them to

XenServer hosts, which can immediately access those volumes as storage repositories. Using the

XenServer EqualLogic Storage Adapter, a volume on the PS Series Group is automatically created as

a virtual hd for a virtual machine and access controls are automatically set for the volume. Using

the book cloning feature of PS series, new virtual machines can be instantly provisioned by cloning

an existing virtual automobile.

Reduced management complexity

EqualLogic PS Serial SANs simplify storage management by consolidating concrete storage and

providing a single-pane management view of the entire virtualized storage pool in the Group. The PS

Series intelligently balances workloads across the available arrays without need for human being intervention,

automatically adapting to changes in workload.

The XenServer EqualLogic Storage Adapter integrates the PS series storage direction directly into

the XenServer and XenCenter interface. Storage volumes for virtual machines can be managed right

from XenCenter or XenServer CLI. Thus virtual car storage deployment and management are

greatly simplified when using EqualLogic storage with XenServer.

eight

High availability

XenServer v.0 introduces an automated local High-Availability feature that protects virtual machines

hosted on shared storage confronting host failures. The virtual machines running on a failed host are

restarted on remaining servers in the XenServer puddle. NIC bonding available in XenServer protects

against failures in either network cards or paths for storage, virtual machine or direction traffic.

EqualLogic PS Series arrays offering best in class reliability, with hot-swappable and fully redundant

components, RAID five/10/50 back up and hot spares.

High scalability

Every bit 1 adds more PS Series array members to a PS Series group, the storage capacity scales along

with the functioning without disrupting application or data availability. Plus the SAN dynamically

balances the load to optimize storage resources.

Using XenServer Resource Pools, once tin hands add new XenServer hosts to an existing pool,

increasing the pool's chapters to meet increased workload demands.

Increased flexibility

The net result of all these features and capabilities is not only a reduced TCO, but increased flexibility.

The ease and speed with which you tin can add new virtual servers or expand concrete storage,

combined with single-pane management and the security of a high-availability infrastructure, allows IT

administrators to respond quickly and flexibly to enterprise demands and initiatives.

SAN features like tiering, load balancing, advanced features in replication and snapshots provide a

higher level of functionality that you tin can't discover in standard stand-lonely direct attached storage.

nine

XenServer storage model and

definitions

XenServer host defines a container chosen a Storage Repository (SR) to describe a particular storage

target, in which Virtual Disk Images (VDIs) are stored. A VDI is a disk brainchild which contains the

contents of a virtual deejay. Figure i illustrates the overall storage model in XenServer.

The interface to storage hardware allows VDIs to be supported on a large number of SR types. With

built-in back up for IDE, SATA, SCSI and SAS drives connected locally, and iSCSI, NFS and Fibre

Channel continued remotely, the XenServer host SR is very flexible. The SR and VDI abstractions

allows advanced storage features such as sparse provisioning, VDI snapshots, and fast cloning to

exist exposed on storage targets, such as Dell EqualLogic PS Series, that support them. For storage

subsystems that do non inherently back up avant-garde operations directly, a software stack is provided

based on Microsoft's Virtual Hard disk drive (VHD) specification which implements these features.

Each XenServer host can use multiple SRs and different SR types simultaneously. These SRs can be

shared, or dedicated between hosts. For shared SR, shared storage is pooled between multiple hosts

within a defined resource pool. A shared SR must be accessible to each host, and thus must exist on

iSCSI, NFS, Fibre Aqueduct or Direct Attached for clusters (such every bit Dell PowerVault MD3000) storage.

Finally, all hosts in a single resource puddle must have at least i shared SR in mutual.

The following 4 object classes that are used to describe, configure, and manage storage:

Storage Repositories (SRs) are storage targets containing homogeneous virtual disks (VDIs). SR

commands provide operations for creating, destroying, resizing, cloning, connecting and discovering the

individual Virtual Deejay Images (VDIs) that they comprise. A storage repository is a persistent, on-disk data

structure. So the act of "creating" a new SR is similar to that of formatting a disk—for most SR types,

creating a new SR involves erasing any existing information on the specified storage target. The exception is

NFS SRs, which create a new directory on the filer leaving existing NFS SRs equally they were. SRs are longlived,

and may in some cases be shared among XenServer hosts, or moved between them.

Physical Block Devices (PBDs) correspond the interface between a physical server and an attached

SR. PBDs are connector objects that allow a given SR to be mapped to a XenServer host. PBDs store

the device configuration fields that are used to connect to and collaborate with a given storage target. For

example, NFS device configuration includes the IP accost of the NFS server and the associated path

that the XenServer host mounts. PBD objects manage the run-fourth dimension attachment of a given SR to a

given XenServer host.

Virtual Deejay Images (VDIs) are on-disk representation of virtual disks provided to VMs. VDIs are the

primal unit of measurement of virtualized storage in XenServer. Similar to SRs, VDIs are persistent, on-deejay objects

that exist independently of XenServer hosts.

Virtual Block Devices (VBDs) are connector objects (similar to the PBD described to a higher place) that allow

mappings betwixt VDIs and Virtual Machines (VMs). In addition to providing a mechanism to attach

(or plug) a VDI into a VM, VBDs allow the fine-tuning of parameters regarding QoS (quality of service),

statistics, and the bootability of a given VDI.

Figure 1: XenServer Storage Model

VM PBD Host

VBD

VBD

VDI

VDI

SR

Dell EqualLogic PS Serial

feature definitions

This section describes some of import PS serial definitions relevant to this paper. Refer to PS Series

online assistance for detailed information on various definitions and features.

Volume

A volume is a logical device representing a portion of storage puddle infinite and seen on the network

as an iSCSI target. Volume information is divided among pool members. Volumes are protected past access

control records.

Thin provisioning

Thin provisioning technology allows one to more than efficiently provision storage, while still meeting

awarding and user storage needs. A book has two capacity sizes associated with information technology:

• The reported size is the size that is seen by iSCSI initiators. Hosts continued to the volume will

associate this amount of infinite with the volume.

• The book reserve is the amount of space that is allocated to the volume.

For a volume without thin provisioning enabled, the reported size and the volume reserve are the aforementioned.

For volume with sparse-provisioning enabled, the reported size is greater than (or equal to) the volume

reserve, because the book is not fully allocated.

A thin-provisioned volume is initially allocated simply a portion of the volume size. As data is written to

the volume, more infinite is automatically allocated (if available), and the book reserve increases up to

a specified limit. Regular upshot messages occur every bit space is used, giving you the opportunity to make

adjustments.

Because thin-provisioned volumes are only allocated the storage infinite that they actually employ, you can

more than efficiently employ storage resources, with no hard resize operations on the calculator.

Thin provisioning is most effective when you know how a volume usage will increase over fourth dimension, the charge per unit

of growth is anticipated, and users practice not demand immediate, guaranteed access to the full book size.

Administrators must monitor sparse-provisioned volumes and exist prepared to increase storage space past

adding or moving arrays to the pool containing the volume. If yous must guarantee the total volume size,

thin provisioning is not recommended.

Volume snapshots

A snapshot is a space-efficient point-in-time representation of volume data. Snapshot cosmos does

not disrupt access to the volume.

Like volumes, snapshots on the network look like iSCSI targets and tin can be set online and accessed by

computers with iSCSI initiators. Yous can recover volume data by restoring a book from a snapshot or

by cloning a snapshot, which creates a new volume.

To create a snapshot, 1 must starting time reserve snapshot space for the volume. Snapshot reserve is taken

from the pool containing the volume, and is based on a pct of the electric current volume reserve.

Group level defaults can be gear up to reserve a specified percentage of volume size for snapshot reserve.

PS Series group snapshot technology uses a reallocate-on-write technique. When users make changes

to the base of operations volume (or to the snapshot), the group stores the changes in the snapshot reserve.

Volume clones

A book clone is an verbal re-create of a volume created from either the original volume or from a snapshot

or replica . Cloning a book creates a new volume with a new name and iSCSI target, just the aforementioned

size, contents, and thin provisioning settings as the original book at the time of the cloning. The

new volume is created in the aforementioned puddle as the original volume and is available immediately. Cloning a

book does not change the original book.

A cloned book consumes 100% of the original volume size from free space in the puddle. If you create

snapshots or replicas of the new volume, they will employ additional pool space. You cannot select a

different storage puddle (if bachelor) during the clone operation, just yous tin move the new volume to

another puddle later.

Volume replicas

Replication engineering science in the PS Series firmware lets you re-create volume data betwixt groups, thereby

protecting the data from a multifariousness of failures, ranging from the destruction of a volume to a complete

site disaster, with no effect on data availability or performance. Similar to a snapshot, a replica is a copy

of a volume at a specific point in time. A replica set is the set of replicas for a volume created over time.

A volume and its replica set are always stored in different groups. By separating the groups

geographically, volume data is protected against a complete site disaster. To replicate data between

ii PS Serial groups, you lot must configure the groups as replication partners . The groups can be in the

same building or an unlimited distance apart.

Each replication partner plays a specific role in the replication of a volume. The volume is stored on

the primary group , while the volume replica set is stored on the secondary group in space that the

secondary group delegates to the principal group. The primary grouping sends (replicates) the data and

the secondary grouping receives the data. Mutual authentication offers security between partners.

The first replication of a volume sends the unabridged contents of the volume to the secondary group.

In subsequent replications, only the information that changed since the previous replication is sent to

the secondary grouping. The longer a replication takes, or the longer the interval between scheduled

replications, the more than the data that might have to exist transferred to the partner.

To recover volume data from replicas in the secondary group, you tin clone an individual replica to

create a new book. Yous can also host a book on the secondary grouping, either temporarily, for

example to practice backups, or permanently (eastward.one thousand. to supercede a failed primary group or to change the roles of

the primary and secondary groups).

If you are hosting the book temporarily on the secondary grouping, yous tin can later fail back to the primary

group and utilize the original replication configuration.

iSCSI storage repositories in

XenServer 5.0

XenServer five.0 hosts can access iSCSI storage using the built in open-iscsi software initiator or an

iSCSI HBA. XenServer 5.0 includes support for two types of iSCSI storage repositories:

LVM over iSCSI or lvmoiscsi SR: utilizes the Linux Volume Managing director (LVM) to create a logical volume

per virtual disk image (VDI) on the iSCSI LUN. The VDIs residing in LVM over iSCSI SRs do not provide

support for sparse provisioning or fast cloning. The SR utilizes the entire LUN specified at creation time

and may not span more than than i LUN.

Dell EqualLogic or equal SR: utilizes the XenServer EqualLogic Storage Adapter to manage virtual

automobile storage on PS Series Group. For each SR of type Dell EqualLogic , a modest management

volume is created on PS Series Group. For each XenServer virtual disk image (VDI) in the SR, a

corresponding book on PS serial group is created. This allows for advanced VM life wheel operations

such every bit snapshots, fast clones, thin provisioning, book resizing etc.

Both LVM over iSCSI and Dell EqualLogic SRs are capable of supporting VM agility using XenMotion:

VMs can exist moved across XenServer hosts in a pool without noticeable reanimation. CHAP support is

provided for customer hallmark, during both the data path initialization and the LUN discovery phases.

LVM over iSCSI vs. Dell EqualLogic

SR usage considerations

When using EqualLogic PS Series to provide iSCSI storage, you should consider storage and feature

requirements to make up one's mind whether to use the specialized Dell EqualLogic SR, or to utilise the generic

LVM over iSCSI SR. The specialized XenServer EqualLogic Storage Adapter enables XenServer to

communicate with the PS Serial group to manage storage for VMs and utilise advanced array features

such as thin provisioning, fast cloning and snapshots. Table 1 below summarizes comparing between

the LVM over iSCSI and EqualLogic SR capabilities.

Features/ Requirements LVM over iSCSI SR Dell EqualLogic SR

Shared SR for XenServer Puddle Yes Yep

XenMotion Aye Yes

Resize Virtual Deejay Prototype (VDI) Aye Yes

Thin Provisioning No Yep

Fast Cloning No Yeah

Virtual Machine Snapshots No Yes

PS Series book management from

XenServer/XenCenter

No Yes

Number of volumes on PS Serial per

Ane for SR; each VDI is a logical

volume

One for SR plus one for each VDI

iSCSI connections per host to PS

series grouping

One per SR One per active VDI

Connection load balancing for an SR

on PS serial group

From a host, connection to an SR

through a single iSCSI port on a

member

Connections to VDI volumes load

balanced across member iSCSI ports

Table one: LVM over iSCSI Vs EqualLogic SR

Setup and configuration

A simple setup utility lets you quickly configure a PS Series array as a member of a new group.

After you cull the RAID type, the array is automatically configured, and the storage is immediately

set up for employ. Data and network I/O are automatically load counterbalanced across the disks and network

interfaces—with no impact on data availability.

To increase SAN capacity and performance, connect another assortment to the network and add it to the

group. Load balancing across the members occurs automatically, as needed. Management overhead

remains the aforementioned, regardless of the group size.

For instructions on initial PS series array configuration, delight refer to the PS Serial Quick Outset Guide

at http://www.equallogic.com/support

Typical PS Series-XenServer setup

This section describes a typical multi XenServer host setup with EqualLogic PS Series Group. As shown

in Figure ii, Citrix XenServer Dell Edition runs on Dell PowerEdge servers, configured in a resources pool.

All XenServer hosts are connected via an Ethernet fabric and share storage on the Dell EqualLogic

PS5000 array(s). The iSCSI traffic is physically isolated from other network traffic using divide physical

Ethernet switches. Ii NICs on each host are bonded to provide loftier availability and load balancing for

host management and virtual car traffic and high availability for IP storage traffic.

Figure 2: A sample of typical XenServer Pool Configuration using PS Series storage

This configuration illustrates traffic segregation using separate physical switches; however, isolation can

too be achieved using VLANs. XenCenter can be installed on any workstation or server machine that

has access to the host direction network.

Note: Refer to XenServer Dell Edition Solution Guide for more data on supported Dell storage configurations with XenServer.

EqualLogic PS

Series Array

XenCenter Client /

Direction Station

XenServer

Hosts

XenServer Management and

XenMotion Traffic

Virtual Machine Traffic

iSCSI Storage Traffic

one

1

2 two

2

1

iii

3

2

3

Multi-pathing with XenServer and PS Serial

Multi-pathing in XenServer for iSCSI traffic is achieved using a highly bachelor bond device on the

XenServer host. In case of failure of a network port, the other network port in the bond takes over the

network traffic. As shown in Figure 2, information technology is recommended to use redundant Ethernet switches to prevent

a path failure at the switch level. Note that load balancing for network traffic over a bail is supported

only for virtual auto traffic and not for IP storage traffic. At any given time, only one NIC, out of ii in

a bond, is used for iSCSI traffic. If the active NIC in a bail fails, the other NIC will take over. Refer to the

XenServer 5.0 Reference Transmission for more information on creating and managing NIC bonds.

The EqualLogic PS arrays have two controllers; only i controller is agile at a given time. Each

controller has 3 network ports for iSCSI connectivity. The XenServer hosts connect to the PS Series

Grouping using the well known accost or the Group IP address rather than the IP address of an iSCSI

port on a member assortment. When an initiator connects to the PS Series Group using the Group IP

address, the group redirects the initiator (via iSCSI redirect functionality) to log-in to an iSCSI port on

a member. The PS serial group intelligently redirects incoming connections to load-rest iSCSI

traffic across iSCSI ports on group members. In example a port on a controller fails, the connections are

redirected to other available ports. In case the active controller fails, the passive controller on a member

becomes active and takes over IP settings of the failed controller.

Note: XenServer 5.0 natively uses dm-multipath for iSCSI traffic where the iSCSI storage arrays expose multiple target portals.

However this is not the case with EqualLogic PS arrays. For this reason, enabling multi-pathing for a XenServer host using

XenCenter or CLI does non utilise dm-multipath functionality.

Sample XenServer host and PS Series network configuration

This department discusses a sample network configuration for a XenServer host and a PS Series group

to create a configuration as illustrated in Figure 2. Effigy 3 shows the XenServer host network

configuration. The host has iv Gigabit LOM ports and two single port Gigabit network adapters.

Using two NIC ports each, three bond devices (for host direction, IP storage and virtual machines)

are created using the XenCenter interface. In XenServer, the host direction interface is used for the

IP traffic by default. Notwithstanding, as a best practice it is recommended to use a dissever host interface

for IP storage traffic. This is accomplished by creating some other host interface on a subnet divide from the

host direction interface.

one. Using XenCenter interface, create a bond device for host direction and virtual automobile

network. Active/active bonding in XenServer v.0 provides both high availability and load balancing

for virtual motorcar and host management traffic. Figure 4 shows the host management interface as

seen in XenCenter interface.

ii. To provide loftier availability for storage traffic, create a bond using two NIC ports.

3. Create a new host interface for storage traffic: in XenCenter interface, click on the host and select

"Direction Interfaces . " Create a new interface and configure the IP settings such that the

storage direction interface is on a separate subnet from the host management interface, and

on the same subnet as the PS Serial Group. Effigy 4 shows storage interface as seen in the

XenCenter interface. Note that the storage interface must be on a separate subnet from the host

management interface to segregate IP storage traffic from host management traffic.

Example XenServer Host IP configuration:

Host Management Interface: 172.17.forty.71/255.255.255.0

Host Storage Interface (bond):172.17.50.115/255.255.255.0

Figure 3: Sample host direction and storage networks on a XenServer host

Figure 4: XenServer Host Networking: Management and Storage Interfaces

Notation: As a best practice, information technology is recommended to employ a static IP address for host management and storage interface.

Instance IP configuration for a PS Serial group with one fellow member:

PS Series Group and member IP configuration:

PS Series Group IP: 172.17.fifty.forty/255.255.255.0

PS Series Fellow member Storage Port (eth0): 172.17.50.41/255.255.255.0

PS Serial Member Storage Port (eth1): 172.17.fifty.42/255.255.255.0

PS Series Member Storage Port (eth2): 172.17.50.43/255.255.255.0

Note: PS Series network configuration requires that the Group IP and the IPs for the fellow member storage ports (eth0, eth1 and eth2)

must all be on the same subnet.

If using a separate management IP (other than the Group IP) to manage a PS Serial grouping, then the

Group IP and storage ports eth0 and eth1 need to be on aforementioned subnet. The direction IP and eth2

for the members should be on the same subnet. For more information on configuring a management

interface (other than the group interface) for a PS Serial grouping, refer to the PS series online help.

Networking best practices for PS Series and XenServer

Refer to the PS Serial Array Network Performance Guidelines document for data on general

network configuration all-time practices for EqualLogic PS Series arrays.

Note: Jumbo frames are non supported in XenServer v.0.

Note: XenServer 5.0 natively uses dm-multipath for iSCSI traffic where the iSCSI storage arrays expose multiple target portals.

However this is not the case with EqualLogic PS arrays. For this reason, enabling multi-pathing for a XenServer host using

XenCenter or CLI does non use dm-multipath functionality.

Creating a storage repository on

PS Series Group

Creating a storage repository of type LVM over iSCSI (lvmoiscsi)

i. Following the instructions available in the PS Serial online aid, configure the PS Serial array,

create a group, set a member RAID policy, create a volume and set appropriate access command

method (using XenServer host IQN or management IP).

2. If creating an SR for a pool, make sure that the storage volume is enabled for shared access from

multiple initiators. To enable shared access, in the PS series group managing director user interface, rightclick

on the volume and select "Modify Book Settings. " Select the Advanced tab and check

"Enable shared admission to the iSCSI target from multiple initiators" (Come across Figure 5).

Figure v: Enable shared access to the SR volume when SR is intended to exist shared

iii. Using the XenCenter interface, right-click on the XenServer host or the pool for which y'all would

like to create SR for and select "New Storage Repository. " Choose the iSCSI radio button for the

type of new storage, and select "Next. "

iv. Enter the proper name for the new SR in the name field, PS series Group IP address in the Target Host

field, and 3260 in the port field. Provide the chap username and password information if configured

for the volume. And so click on "Discover IQNs" to perform target discovery. Each volume on a PS

Series array has a unique target proper name with LUN ID prepare to "0." Select the appropriate IQN and and so

click on "Discover LUNs" to discover the LUN or volume associated with the target. Select the

book and click "Finish" to create a new SR.

xix

Creating a storage repository of type Dell EqualLogic (equal)

Note: To utilize an SR of type Dell EqualLogic , the firmware version of PS Series arrays must be 4.0.1 or higher.

To create a storage repository of blazon Dell EqualLogic or equal , follow the steps below:

ane. Following the instructions bachelor in the PS Series online help, configure the EqualLogic array,

create a group, set a member RAID policy, and create a volume.

2. Using the PS Serial Group Manager User Interface, make sure that SSH access is enabled on

the group members. Click on the "Group Configuration" and select the "Administration" tab. If non

already enabled, check the "Enable SSH (secure shell)" admission checkbox in the CLI admission options

for the grouping and save the configuration.

3. Using the XenCenter interface, correct-click on the XenServer host or the pool for which you

would like to create SR for and select "New Storage Repository. "

4. In the "Choose the type of new storage window" , select "Dell EqualLogic" (encounter Effigy half-dozen) and

click "Next. "

Effigy six: Select Dell EqualLogic to create an SR of type Dell EqualLogic

5. In the "Enter the Dell EqualLogic filer details" window, provide a name for the SR in the proper name

field, the Group IP of your PS Series group, and the user name and password for an account with

administrative privileges for group or a pool. Optionally, provide CHAP credentials if set on the PS

Series group and click "Next. "

6. The following screen provides two options: Reattach an existing SR or create a new SR. Choose

the "Create a new SR on the following storage puddle" radio button. Y'all can see the details on the

available storage pool including the size, costless available space, number of existing volumes and

members in the pool.

If yous similar all VDIs in the SR to be thin provisioned, select the "Thin Provisioning" checkbox when

creating the new SR (see Figure vii).

Click "End" to create a new SR.

Effigy 7: Select the appropriate storage pool and thin provisioning settings for EqualLogic SR

As shown in Figure 8, upon completion of the SR creation procedure, a respective book of size

20MB is created on the PS Series Grouping. When calculation an SR to the pool, admission command records for

all XenServer hosts in the pool are added to the volume. The admission control is specified by the IQN of

the XenServer host.

Note: Volume name and description fields are used by XenServer EqualLogic Storage Adapter to manage volumes on the PS Serial

Group. Do not manually change the name and description fields for whatever book automatically created by a XenServer host.

Figure 8: SR volume every bit shown in PS Series Group GUI

Identifying XenServer storage objects on a PS Serial Group

For Dell EqualLogic SR, an SR is only a logical group of VDIs or volumes on the PS Series Group.

The naming scheme for volumes automatically created by XenServer EqualLogic Storage Adapter is

as follows:

At the signal the SR is created, a management volume is provisioned on the PS Serial Grouping. This

serves to identify the persistent SR presence on the group, as well as providing a location to shop SR

metadata every bit required by XAPI. The management book is named as:

"XenStorage<SR_UUID>MANAGEMENT"

where SR_UUID is the UUID of the storage repository.

For instance, in Figure 9, the volume

XenStorageb93f1728dd0c6077e96dbc968a047fb2MANAGEMENT

corresponds to an SR with UUID b93f1728dd0c6077e96dbc968a047fb2

Each volume corresponding to a VDI within an SR is identified by the identification string "XenStorage"

followed by the SR UUID, and a cropped version of the VDI UUID. The total VDI UUID is stored in the

Volume description field.

For example, every bit shown in Figure 9 the volume with name

XenStorageb93f1728dd0c6077e96dbc968a047fb22332cdcae4fd4a3d9bbc

corresponds to a VDI. The VDI is related to SR with UUID b93f1728dd0c6077e96dbc968a047fb2

and the cropped UUID of VDI is 2332cdcae4fd4a3d9bbc . The total UUID of VDI is available in the

volume description.

Figure 9: A VDI book equally shown in PS Series Group GUI

Note: The XenServer EqualLogic Storage Adapter uses volume proper noun and description fields to reference volumes on PS Series

Group. Manually changing either the volume proper noun or clarification fields to values other than those assigned past the XenServer

storage adapter may lead to failure in storage management tasks.

Typical lifecycle tasks for VMs on

Dell EqualLogic SR

This section describes typical virtual car life bicycle operations for virtual machines created and

managed using the XenServer EqualLogic Storage Adapter.

Create a virtual machine

The process to create a virtual machine with storage on Dell EqualLogic PS serial group remains the

aforementioned as with whatever other storage backend. While creating a VM, just select the appropriate SR created

on your PS Serial Group. For more than information on creating virtual machines, refer to XenServer Virtual

Automobile Installation Guide .

Create a VDI

When using an SR of type Dell EqualLogic , for each Virtual Disk Epitome (VDI) created on a XenServer

host, a corresponding book is created on the PS Series Group. Effigy 9 shows a volume, with name

XenStorageb93f1728dd0c6077e96dbc968a047fb22332cdcae4fd4a3d9bbc , that has been

automatically created by the XenServer EqualLogic Storage Adapter.

The size of the volume on the array is same every bit the VDI size specified by the user.

Note: When a VDI is created using XenCenter, the corresponding book created on the PS series Group inherits the default grouping

volume and thin provisioning settings.

To create a VDI using CLI utilize the xe vdi-create command:

# xe vdi-create virtual-size=10GiB name-label=testvdi

sr-uuid=<SR UUID> type=user sm-config:allocation=<thin | thick>

sm-config:snap-reserve-percentage= <Percentage Integral Value>

sm-config:snap-depletion=<delete-oldest | book-offline>

where SR_UUID is the UUID of the SR of blazon Dell EqualLogic

sm-config:allocation controls whether the VDI book is provisioned as a thin volume or non. Setting

sm-config:resource allotment=sparse will create a volume with sparse provisioning enabled. Setting

sm-config:allotment=thick volition create a volume with sparse provisioning disabled. If blazon of

allocation is non specified, the default allocation for the SR is used to provision the VDI volume.

sm-config:snap-reserve-percentage specifies amount of space, in terms of per centum of

book, to reserve for book snapshots. If snap-reserve-percentage is non specified, the group

default value for snapshot reserve is used.

sm-config:snap-depletion specifies the snapshot space recovery policy:

action taken when the space reserved for snapshots has been exceeded. Setting

sm-config:snap-depletion =delete-oldest deletes the oldest snapshots until sufficient

space is recovered (the default). Setting sm-config:snap-depletion=volume-offline sets

the volume and snapshots offline. Agile iSCSI connections will be terminated before a snapshot is

automatically deleted.

For example, the following command to create a new VDI

# xe vdi-create virtual-size=10GiB name-label=vdi1 blazon=user

sr-uuid=b93f1728-dd0c-6077-e96d-bc968a047fb2 sm-config:allotment=sparse

sm-config:snap-reserve-percent=l sm-config:snap-depletion=delete-oldest

provisions a book, on PS Series Grouping, of size 10GB, with a snapshot reserve of 50% of volume size

(10GB), thin provisioning enabled and snapshot infinite recovery policy to delete oldest snapshot.

Delete a VDI

Deleting a VDI deletes the associated volume on the PS Series Grouping. However if a VDI has any

associated snapshot, deleting a VDI from XenServer host volition not delete the parent volume on PS

series Group until the last existing snapshot is deleted.

A VDI can be deleted or destroyed using the XenCenter interface or using a vdi-destroy command.

# xe vdi-destroy uuid=<VDI_UUID>

Resize a VDI

To resize a VDI from XenCenter, correct click on the VDI and select Edit Virtual Disk . Modify the size of the

VDI and click OK .

To resize a VDI using CLI, use the xe vdi-resize command:

# xe vdi-resize uuid=<VDI_UUID> deejay-size=<new size>

where VDI_UUID is the UUID of the VDI under consideration

new size the new size of the VDI.

For case, the following command sets the size of the VDI to 50GB:

# xe vdi-resize uuid=6be5ed34-7600-4218-a68e-741aeb4ee815 disk-size=50GiB

When a VDI is resized using XenCenter or CLI, the size of the corresponding volume on PS serial

group is also ready to the new size value specified for the VDI. The snapshot reserve for the book is

also automatically adjusted to comply with the predefined per centum of volume size.

Copy or clone a VM

A copy or clone of a VM can exist created in 2 ways:

Fast Clone —Uses PS Series volume clone feature to instantaneously create clones of volumes

respective to VDIs attached to the virtual machine.

Full Re-create —Creates a copy of the source virtual machine storage volumes by copying all data over to

new volumes. Depending on the size of data to be copied, a total copy operation may take from a few to

several minutes to complete.

The XenServer fast cloning feature utilizes PS Series book cloning to provision new virtual machines

within seconds. To provision a new VM using fast cloning, right click on the source VM and select

"Copy VM. " Provide a name and clarification for new VM and select "Fast Clone" equally the re-create style

(see Figure 10). Click "Re-create" to finish creating a new VM that is a copy of a specified source VM.

Figure x: Fast cloning characteristic uses PS Series volume cloning to instantaneously provision new VMs

Deploy from Template

A template is a "gold paradigm" that contains all the configuration settings to instantiate a specific VM.

With XenServer 1 can create VMs, configure them in standard forms for detail needs, and salvage a

copy of each as a template for hereafter use in VM deployment.

If all the VDIs of the template VM reside on an SR of blazon Dell EqualLogic , when deploying a new VM,

in the same SR, from the template, XenServer uses the PS Series cloning feature to instantaneously

provision a new virtual car. However if a VM is deployed to an SR other than the SR where

template resides, XenServer provisions the new VM by copying.

Snapshot a VM

XenServer provides a convenient VM snapshot mechanism that can accept a snapshot or capture a

signal-in-fourth dimension copy of a VM's storage and metadata. Where necessary, I/O is temporarily halted while

the snapshot is beingness taken to ensure that a self-consistent disk prototype can be captured.

Snapshot operations outcome in a snapshot VM that is like to a template. The VM snapshot

contains all the storage data and VM configuration, including attached VIFs, allowing them

to be exported and restored for fill-in purposes. XenServer 5.0 besides includes a Xen VSS provider

(installed equally part of Citrix XenTools) to enable quiesced snapshots. Quiesced snapshots take

reward of the Windows Volume Snapshot Service (VSS) for services that back up it, so that a

supported application (for case Microsoft Exchange or SQL Server) tin can flush data to deejay and

prepare for the snapshot before it is taken.

For virtual machines residing on SR of type Dell EqualLogic , when a snapshot operation is issued,

XenServer EqualLogic Storage Adapter instructs the PS Series Group to take a snapshot of the

volumes associated with the virtual machine's VDIs. Snapshots are supported for only Dell EqualLogic

SRs and non for an SR of type LVM over iSCSI .

A snapshot on the PS series is treated as a carve up target and gets its ain IQN. When virtual

machine snapshots are created from a XenServer host, access control records (specified by host IQN)

for the snapshots are automatically created to allow the XenServer or a group of XenServer hosts in a

pool to admission the snapshots.

Figure eleven shows a virtual machine win2003_vm1 which has 2 VDIs. Nether the Virtual Disks tab on

XenCenter, snapshots for the VDIs appear for each VDI. The respective view on PS Series GUI is

shown in Figure 12.

Effigy 11: VM snapshots as shown in XenCenter Interface

Figure 12: VM snapshots as shown in PS Series Grouping UI

XenServer treats snapshots as templates. As seen in Figure 11, the snapshot win2k3_vm1_snap1 of

virtual automobile win2k3_vm1 is also listed as a custom template. But like regular templates, one can

instantaneously deploy new virtual machines from such snapshots. When a new VM is deployed from a

snapshot, XenServer uses the snapshot clone feature of the PS series arrays to instantaneously create

clones of snapshots associated with the source VM. Access control records (specified by host IQN) for

newly cloned volumes are automatically created to allow a XenServer or a group of XenServer hosts in

a puddle to access the volumes.

Refer to the XenServer Reference Guide for more than information on regular and quiesced snapshots.

Restore a VM from a Snapshot

A virtual motorcar can be restored to a snapshot state if needed. One tin restore the VDI volumes

on PS series from snapshots; however ane must restore all volumes fastened to a VM. Some other

way to restore a VM from the snapshot country is to create a new virtual automobile from a snapshot

and conciliate or delete the old VM. Follow the steps in the VM Rollback section in XenServer 5.0

Reference Guide for instructions on how to restore a VM from a snapshot.

Delete a VM

When a VM is uninstalled, all the volumes, on the PS Series Group, associated with the virtual machine

are deleted. When the volumes are deleted, the storage space is marked as free and returned to the

storage pool.

If a virtual machine has whatsoever associated snapshots, deleting a virtual machine does not delete the

volumes associated with virtual auto VDIs. When the final available snapshot associated with the

virtual machine is deleted, the parent book gets deleted as well.

Delete a Snapshot

When a snapshot of a virtual motorcar is deleted or uninstalled, the respective snapshots of all

volumes (on PS Serial) for VM VDIs are deleted from the PS Series Group. To delete or uninstall a

snapshot, click on the template respective to the snapshot and select Uninstall Template.

Using PS Series replication with

XenServer Portable SRs

XenServer five.0 introduces the concept of Portable Storage Repositories (Portable SRs). Portable SRs

contain all of the information necessary to recreate all the Virtual Machines (VMs) with Virtual Disk

Images (VDIs) stored on the SR after re-attaching the SR to a different host or pool. Portable SRs can

be used when regular maintenance or disaster recovery requires manually moving a SR betwixt pools

or standalone hosts.

Portable SRs work by creating a dedicated metadata VDI within the specified SR. The metadata VDI

is used to shop copies of the pool or host database as well as the metadata describing each VM's

configuration. Equally a result the SR becomes fully self-contained, or portable, allowing it to be discrete

from one host and re-attached to some other as a new SR. Once the SR is re-fastened, a restore process

is used to recreate all of the VMs on the SR from the metadata VDI.

For disaster recovery the metadata backup can be scheduled to run regularly to ensure that the

metadata SR is current. For more than information on XenServer 5.0 portable SRs and restrictions on

usage, refer to the XenServer v.0 Reference Transmission.

Using replication for SR of type LVM over iSCSI

When using replication to protect storage repositories of blazon LVM over iSCSI , one needs to configure

replication for volumes backing the SRs.

ane. Configure a replication partner (secondary) group for the primary PS Series group.

2. Configure replication for the appropriate SR volume(s). Replication schedules to create replicas at

specific intervals can exist created for the volumes accessible to XenServer hosts.

iii. On the primary XenServer host or pool, use the pool master console interface to schedule VM

metadata backup on the protected Storage Repository. Make certain that replication is configured for

the SR that holds pool or host metadata.

Note: For suspended VMs, delight make sure to replicate the designated append SR.

On the secondary site, the replicas may be used to perform backup operations or for disaster recovery

operations should the principal site becomes unavailable. In gild to adhere the SR on XenServer host/

pool on the secondary site:

i. In one case the replicas for the replicated SR volume are in the Fix state, promote the replica as

a volume or create a replica clone. Annotation that past default, replica clones accept thin provisioning

enabled.

2. For the replica clone, add appropriate access command records for XenServer hosts on the

secondary site to access the SR volume(s). For shared SRs, make sure to enable shared access

for the SR volume(s).

3. On the XenServer host or pool master on the secondary site, attach the replica clone or promoted

book as an existing SR.

iv. Using the Restore Virtual Motorcar Metadata pick from XenServer local console, restore the VM

metadata to recover all virtual machines on the replicated SR book.

Using replication for SR of type Dell EqualLogic

Using replication with SRs of blazon Dell EqualLogic is footling different from replication with SRs of blazon

LVM over iSCSI . Dissimilar LVM over iSCSI SRs were all VDIs reside on a single volume on PS Series

Group, each VDI for Dell EqualLogic SRs, is backed by its own volume on the PS Series Grouping.

Hence replication needs to exist configured for the SR and all the associated VDI volumes.

For SR of type Dell EqualLogic, in lodge to recover VMs on the secondary site:

1. Configure a replication partner (secondary) group for the chief PS Series group.

two. On the primary XenServer host or pool, utilise the pool master console interface to schedule VM

metadata backup on a protected Storage Repository. This process will create a new 255MB

volume on the PS Series Group. This volume holds the pool and VM metadata.

three. Configure replication for the SR volume and all associated VDI volumes, including the metadata

VDI. Autonomously from creating one-fourth dimension replicas, a replication schedule can also be created to create

replicas at specific time intervals for all replicated volumes.

On the secondary site, the replicas may be used to perform fill-in operations or for disaster recovery

operation if the primary site is unavailable. In society to attach the SR on the replication partner:

1. Once the replicas for the replicated SR volume are in the Ready state, create clones of the SR

book and all VDI volumes, including the metadata VDI volume. Annotation that by default, replica

clones accept thin provisioning enabled.

Annotation: When creating clones from replicas make sure than the name and description of each clone is set to exist exactly aforementioned

as source volumes. Failure to do and so will forestall the XenServer hosts in the secondary site to reattach the SR and automatically

recover the VMs using the metadata VDI.

Note: A temporary volume promoted, from a replica and with the ability to demote to a replica set has a proper name and description

unlike than source book. Hence, recovering VMs using such temporary volumes at replication site is not viable at this fourth dimension.

2. For shared SRs, make sure to enable shared access for the SR and all VDI volumes. Access

control records for all volumes are automatically created by the XenServer EqualLogic Storage

Adapter.

three. On the XenServer host or pool principal on the replication site, attach the replica clone as an

existing SR.

iv. Using Restore Virtual Machine Metadata option from XenServer local console, restore the VM

metadata to recover all virtual machines on the replicated SR volume.

References

XenServer Dell Edition Documentation: http://www.dell.com/back up/home/us/en/04/product-back up/product/dell-venue-11i-pro/manuals

Dell EqualLogic PS Series Online help: http://psonlinehelp.equallogic.com/V4.0/

XenServer 5.0 User Documentation: https://www.citrix.com/xenserver/dell

PS Series Array Network Operation Guidelines:

http://www.equallogic.com/uploadedfiles/Resource/Tech_Reports/tr-network-guidelines-TR1017.pdf

About Citrix

Citrix Systems, Inc. (NASDAQ: CTXS) is the global leader in access infrastructure and the most trusted proper name in secure admission. More than

than 200,000 organizations around the world utilize the Citrix Access Platform to provide secure, well-managed access to business

information wherever it lives—on demand. Citrix customers include 100 percent of the Fortune 100 companies, 99 percentage of the

Fortune 500, and 97 percent of the Fortune Global 500, in addition to hundreds of thousands of smaller businesses and individuals.

Based in Fort Lauderdale, Florida, Citrix has offices in 22 countries and approximately six,200 channel and alliance partners in more than

than 100 countries. Annual revenue in 2007 was $1.4 billion.

Almost Dell

Dell Inc. (NASDAQ: DELL) listens to customers and delivers innovative technology and services they trust and value. Uniquely

enabled past its direct business model, Dell is a leading global systems and services company and No. 34 on the Fortune 500. For

more than information, visit www.dell.com, or to communicate directly with Dell via a diversity of online channels, go to HYPERLINK

"http://world wide web.dell.com/" www.dell.com/ conversations. To go Dell news straight, visit HYPERLINK "http://www.dell.com/RSS" www.

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Lawrence Belisho

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