Citrix Systems 5.6 Pool failures, Coping with Failure due to Configuration Errors, Physical Machine failure

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If you repair or replace the server that was the original master, you can simply bring it up, install the

XenServer host software, and add it to the pool. Since the XenServer hosts in the pool are enforced to be

homogeneous, there is no real need to make the replaced server the master.

When a member XenServer host is transitioned to being a master, you should also check that the default

pool storage repository is set to an appropriate value. This can be done using the xe pool-param-list

command and verifying that the default-SR parameter is pointing to a valid storage repository.

Pool failures

In the unfortunate event that your entire resource pool fails, you will need to recreate the pool database from

scratch. Be sure to regularly back up your pool-metadata using the xe pool-dump-database CLI command

(see the section called “pool-dump-database”).

1. Install a fresh set of hosts. Do not pool them up at this stage.

2. For the host nominated as the master, restore the pool database from your backup using the xe pool-

restore-database (see the section called “pool-restore-database”) command.

3. Connect to the master host using XenCenter and ensure that all your shared storage and VMs are

available again.

4. Perform a pool join operation on the remaining freshly installed member hosts, and start up your VMs

on the appropriate hosts.

Coping with Failure due to Configuration Errors

If the physical host machine is operational but the software or host configuration is corrupted:

1. Run the command:

xe host-restore host=<host> file-name=<hostbackup>

2. Reboot to the host installation CD and select Restore from backup.

Physical Machine failure

If the physical host machine has failed, use the appropriate procedure listed below to recover.

Warning:

Any VMs which were running on a previous member (or the previous host) which has failed will still be

marked as Running in the database. This is for safety-- simultaneously starting a VM on two different hosts

would lead to severe disk corruption. If you are sure that the machines (and VMs) are offline you can reset

the VM power state to Halted:

xe vm-reset-powerstate vm=<vm_uuid> --force

VMs can then be restarted using XenCenter or the CLI.

1. Run the commands: