Setup Guide

Best Practices 55
Restoring VM Metadata to Recover VMs from a Snapshot
To restore the VM metadata to recover VMs from a Snapshot:
1
Access the Backup, Update and Restore menu in the local console on the
XenServer host or pool master.
2 Perform a metadata restoration operation using the Restore Virtual
Machine Metadata
menu option.
The metadata restoration operation can restore only VM records
associated with the selected SR, or all of the VM records found potentially
from other SRs which were present at the time of the backup.
NOTE: There is also an option to test which VMs are imported without
actually performing the restoration operation.
Adjusting SCSI Timeouts to Tolerate Storage
Controller Failures
To account for time that an I/O may take to complete in a case where the
Dell PowerVault MD3000 or the PowerVault MD3000i storage array goes
through exception recovery on I/O operations, it is recommended to adjust
the SCSI timeouts on XenServer hosts and VMs that are resident on the SRs
on the PowerVault MD3000 or the PowerVault MD3000i storage arrays.
Adjusting SCSI Timeouts for the PowerVault MD3000 RAID Enclosure
If the XenServer host is connected to the PowerVault MD3000 RAID
enclosure, you can adjust the SCSI timeout of the Windows VMs residing on
the SR resident on the PowerVault MD3000 RAID enclosure by changing the
registry settings. Follow the steps below:
1
Navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\dis
k\TimeOutValue
.
2 Create the value if it is not present. Set this value to 200 .
NOTE: Do not modify the SCSI timeout in the paravirtualized Linux VMs as the VM
virtual disks are not presented as SCSI disks.