TOPIC:

Is it possible to set this up with an existing XEN host and a new one built up for the purposes of HA?

Existing host is running a few VMs currently and would like to avoid extended downtime of entirely reconfiguring it for this HA method.

It is possible to set up on an existing host. The SW packages (ha-lizard and iscsi-ha) do not impact any of the normal operations of the host.

However - not knowing your exact setup and transition plan, you should consider the following possible scenarios:

- If you are just adding ha-lizard (not iscsi-ha for local storage HA) then adding ha-lizard is very safe and easy to do.. This assumes that your current VMs are using a SAN for storage.

- If you are adding ha-lizard + iscsi-ha (per our published reference design) - then this is also safe as long as the the current VMs DO NOT occupy the same block storage devices you intend to use for iscsi-ha.

- If you are adding ha-lizard + iscsi-ha and your current VMs reside on the same block storage device that you intend to turn into iscsi-ha storage - then this can be dangerous and is not recommended unless you are confident in backing up and restoring the existing LVs for the VMs.