Citrix Systems 6 Moving Virtual Disk Images VDIs Between SRs, Adjusting the Disk IO Scheduler

6. Click Repair to create and plug a PBD for each host in the pool.

Moving Virtual Disk Images (VDIs) Between SRs

The set of VDIs associated with a VM can be copied from one SR to another to accommodate maintenance requirements or tiered storage configurations. XenCenter provides the ability to copy a VM and all of its VDIs to the same or a different SR, and a combination of XenCenter and the xe CLI can be used to copy individual VDIs.

Copying All of a VMs VDIs to a Different SR

The XenCenter Copy VM function creates copies of all VDIs for a selected VM on the same or a different SR. The source VM and VDIs are not affected by default. To move the VM to the selected SR rather than creating a copy, select the Remove original VM option in the Copy Virtual Machine dialog box.

1.Shutdown the VM.

2.Within XenCenter select the VM and then select the VM > Copy VM menu option.

3.Select the desired target SR.

Copying Individual VDIs to a Different SR

A combination of the xe CLI and XenCenter can be used to copy individual VDIs between SRs.

1.Shutdown the VM.

2.Use the xe CLI to identify the UUIDs of the VDIs to be moved. If the VM has a DVD drive its vdi-uuidwill be listed as <not in database> and can be ignored.

xe vbd-list vm-uuid=<valid_vm_uuid>

Note:

The vbd-listcommand displays both the VBD and VDI UUIDs. Be sure to record the VDI UUIDs rather than the VBD UUIDs.

3.In XenCenter select the VM Storage tab. For each VDI to be moved, select the VDI and click the Detach button. This step can also be done using the vbd-destroycommand.

Note:

If you use the vbd-destroycommand to detach the VDI UUIDs, be sure to first check if the VBD has the parameter other-config:ownerset to true. If so, set it to false. Issuing the vbd-destroycommand with other-config:owner=truewill also destroy the associated VDI.

4.Use the vdi-copycommand to copy each of the VM VDIs to be moved to the desired SR.

xe vdi-copy uuid=<valid_vdi_uuid> sr-uuid=<valid_sr_uuid>

5.Within XenCenter select the VM Storage tab. Click the Attach button and select the VDIs from the new SR. This step can also be done use the vbd-createcommand.

6.To delete the original VDIs, within XenCenter select the Storage tab of the original SR. The original VDIs will be listed with an empty value for the VM field and can be deleted with the Delete button.

Adjusting the Disk IO Scheduler

For general performance, the default disk scheduler noop is applied on all new SR types. The noop scheduler provides the fairest performance for competing VMs accessing the same device. To apply disk QoS (see the section called “Virtual Disk QoS Settings”) it is necessary to override the default setting and assign the cfq disk scheduler

57