Citrix Systems Understanding Citrix Shadow Memory and System Memory Multiplier

vm-memory-shadow-multiplier-set

vm-memory-shadow-multiplier-set [<vm-selector>=<vm_selector_value>...] [multiplier=<float_memory_multiplier>]

Set the shadow memory multiplier for the specified VM.

This is an advanced option which modifies the amount of shadow memory assigned to a hardware-assisted VM. In some specialized application workloads, such as Citrix XenApp, extra shadow memory is required to achieve full performance.

This memory is considered to be an overhead. It is separated from the normal memory calculations for accounting memory to a VM. When this command is invoked, the amount of free XenServer host memory will decrease according to the multiplier, and the HVM_shadow_multiplier field will be updated with the actual value which Xen has assigned to the VM. If there is not enough XenServer host memory free, then an error will be returned.

The VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors for more information).

vm-migrate

vm-migrate[[host-uuid=<destination XenServer host UUID> ] [host=<name or UUID of destination XenServer host> ]] [<vm-selector>=<vm_selector_value>...] [live=<true false>]

Migrate the specified VMs between physical hosts. The host parameter can be either the name or the UUID of the XenServer host.

By default, the VM will be suspended, migrated, and resumed on the other host. The live parameter activates XenMotion and keeps the VM running while performing the migration, thus minimizing VM downtime to less than a second. In some circumstances such as extremely memory-heavy workloads in the VM, XenMotion automatically falls back into the default mode and suspends the VM for a brief period of time before completing the memory transfer.

The VM or VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors). Optional arguments can be any number of the VM parameters listed at the beginning of this section.

vm-reboot

vm-reboot[<vm-selector>=<vm_selector_value>...] [force=<true>]

Reboot the specified VMs.

The VM or VMs on which this operation should be performed are selected using the standard selection mechanism (see VM selectors). Optional arguments can be any number of the VM parameters listed at the beginning of this section.

Use the force argument to cause an ungraceful shutdown, akin to pulling the plug on a physical server.

vm-recover

vm-recover<vm-uuid>[<database>] [<vdi-uuid>] [<force>]

Recovers a VM from the database contained in the supplied VDI.

vm-reset-powerstate

vm-reset-powerstate[<vm-selector>=<vm_selector_value>...] {force=true}

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