Citrix Systems 6.1.0 manual VM Boot Behavior, Implementation Details and Troubleshooting

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5.1.3. VM Boot Behavior

There are two options for the behavior of a VM VDI when the VM is booted:

1.Shared Desktop Mode

On VM boot, the VDI is reverted to the state it was in at the previous boot. All changes while the VM is running will be lost when the VM is next booted.

Select this option if you plan to deliver standardized desktops to which users cannot make permanent changes.

2.Private Desktop Mode

On VM boot, the VDI is in the state it was left in at the last shutdown.

Select this option if you plan to allow users to make permanent changes to their desktops.

5.1.3.1. VM Caching Behavior Settings

The VDI flag allow-cachingdictates the caching behavior:

5.1.3.1.1. Shared Desktop Mode

For shared desktops, the on-bootoption is set to reset and the allow-cachingflag is set to true, new VM data is written only to local storage – there will be no writes to shared storage. This means that the load on shared storage is significantly reduced. However the VM cannot be migrated between hosts.

5.1.3.1.2. Private Desktop Mode

For private desktops, the on-bootoption is set to persist and the allow-cachingflag is set to true, new VM data is written to both local and shared storage. Reads of cached data do not require I/O traffic to shared storage so the load on shared storage is somewhat reduced. VM Migration to another host is permitted and the local cache on the new host is populated as data is read.

5.1.4. Implementation Details and Troubleshooting

Q:Is IntelliCache compatible with XenMotion and High Availability?

A:You can use XenMotion and High Availability with IntelliCache when virtual desktops are in Private mode, that is when on-boot=persist

Warning:

A VM cannot be migrated if any of its VDIs have caching behavior flags set to on- boot=reset and allow-caching=true. Migration attempts for VMs with these properties will fail.

Q:Where does the local cache live on the local disk?

A:The cache lives in a Storage Repository (SR). Each host has a configuration parameter (called local-cache- sr) indicating which (local) SR is to be used for the cache files. Typically this will be a EXT type SR. When you run VMs with IntelliCache, you will see files inside the SR with names <uuid>.vhdcache. This is the cache file for the VDI with the given UUID. These files are not displayed in XenCenter – the only way of seeing them is by logging into dom0 and listing the contents of /var/run/sr-mount/<sr-uuid>

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Contents Citrix XenServer 6.1.0 Installation Guide Trademarks Contents Using Scvmm and Scom with XenServer Boot From SAN Environments Benefits of Using XenServer Administering XenServerWelcome About This DocumentNew Features in XenServer XenServer EditionsXenServer Documentation Guest EnhancementsReferences System Requirements System RequirementsXenServer Host System Requirements XenCenter System Requirements Supported Guest Operating SystemsInstalling XenServer and XenCenter Installation Media and MethodsInstalling the XenServer Host To install or upgrade the XenServer hostPage Installing XenCenter To install XenCenterHost Partition Format Connecting XenCenter to the XenServer Host To connect XenCenter to the XenServer hostInstallation and Deployment Scenarios High-level procedureXenServer Hosts with Local Storage Basic hardware requirementsPools of XenServer Hosts with Shared Storage XenServer Hosts with Shared NFS StorageConfiguring your iSCSI storage XenServer Hosts with Shared iSCSI StorageConfiguring an iSCSI IQN for each XenServer host Xe pool-param-set uuid=pooluuid default-SR=iscsisharedsruuid Enabling on Host Installation XenServer and IntelliCacheIntelliCache Deployment To enable local caching, enter the following commands Converting an Existing Host to Use Thin ProvisioningVM Boot Behavior Implementation Details and TroubleshootingXe sr-list params=local-cache-sr,uuid,name-label Using Scvmm and Scom with XenServer How to install the Integration Suite Supplemental PackIntegration Requirements for Scvmm Integration Requirements for Scom Rolling Pool Upgrades Upgrading XenServerPage Before You Upgrade Upgrading XenServer Hosts Using the xe CLI Before you begin your rolling pool upgradeTo upgrade a pool of XenServer hosts using the xe CLI Upgrading a Single XenServer Host Using the xe CLI Before You Upgrade a Single XenServer HostUpgrading a Single XenServer Host Using the xe CLI To empty the CD/DVD drive of a VM using the xe CLITo upgrade a single XenServer host using the xe CLI Page Upgrading LVM-based SRs using the xe CLI Upgrading LVM Storage from XenServer 5.0 or EarlierApplying Updates and Hotfixes to XenServer Before You Apply an Update or HotfixBefore you begin updating To update individual hosts using XenCenter To update individual hosts using the xe CLIUpdating Individual XenServer Hosts To update a pool of hosts using XenCenter Updating a Pool of XenServer HostsTo update a pool of XenServer hosts using the xe CLI Licensing XenServer Activating a Free XenServer ProductTo activate a free XenServer product Licensing XenServer Editions To license XenServer Advanced editions and higherTo configure licensing for XenServer hosts using XenCenter To configure licensing for XenServer hosts using the xe CLIAdditional Licensing Information Grace Period Appendix A. Troubleshooting To capture and save the log fileAppendix B. Boot From SAN Environments Appendix C. PXE Boot Installations Configuring your PXE Environment for XenServer InstallationTo configure your Tftp server Creating an answer file for unattended PXE installation Preparing the destination systemElement Description Required? Element Description Required? Element Proto dhcp or static
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