Setup Guide

Best Practices 53
3 Take a snapshot of the SR and the Suspend SR if it is different from the
SR for which the snapshot was created.
4 Power on the VMs on the primary XenServer host.
5 Attach the snapshot of the SR and Suspend SR if it is different from the
SR for which the snapshot was created on the secondary XenServer host.
6 Restore the VM metadata to the recovered VMs.
7 Boot the VMs on the secondary XenServer host.
Snapshot a volume when VMs are running
In this scenario, you initiate a snapshot operation on an SR when the VM is in
a running state and performing I/O operations to the storage volume. Unlike
the scenarios described above, there is no service downtime.
In LVM-based SRs, if you take a storage volume snapshot it results in a file
system and application crash consistent snapshot.
When you run an
iSCSI initiator inside the VM to connect directly to SAN
volumes, in which the I/O operations to virtual disks is entirely controlled by the
VM
, you can use array-based snapshots. You can also use frameworks such as
Microsoft VSS or VDS to create application-consistent snapshots. This
approach is useful when each virtual disk of a VM is a separate volume on
storage array.
Backup the VM Metadata
This section explains the steps required to backup the VM metadata from the
primary XenServer host. This metadata can then be restored on the secondary
XenServer host where VMs need to be recovered.
To back up the VM metadata:
1
Access the Backup, Update and Restore menu in the local console on the
XenServer host or pool master.
2 Trigger an immediate metadata backup to the SR being moved using the
Backup Virtual Machine Metadata menu option. The metadata backup
creates a backup virtual desktop infrastructure (VDI), if necessary, and
attaches it to the host, and then backs up all the metadata to that SR.