Citrix Systems 6 manual Pool failures, Coping with Failure due to Configuration Errors

If the master is really dead, choose one of the members and run the command xe pool-emergency-transition-to-masteron it. Once it has become the master, run the command xe pool-recover-slavesand the members will now point to the new master.

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-listcommand and verifying that the default-SRparameter 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-databaseCLI command (see the section called “pool-dump-database”).

To restore a completely failed pool

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:

To restore host software and configuration

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.

Replacing a failed master with a still running member

1.Run the commands:

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