Cluster Architecture with ZFS Replication

[jflorchi]

Hello,

I'm currently in the planning stage of creating a new cluster. My current plan is to have 2 servers, each installed on top of a ZFS10 setup (2 mirrored vdevs) and then setup ZFS replication with a fairly short replication cycle. I don't need true high availability so I don't need quorum. I just need the ability to migrate between the 2 hosts quickly, and start the VM on the other host if it died. If I end up wanting quorum, I will just add a witness node to the cluster.

I have 2 questions with the above setup:

1. If I was to manually trigger a live migration, would it only copy the differential between the last replication and the current running VM disk?
2. Do you foresee any problems with this design?

 

[fabian]

Hello,

I'm currently in the planning stage of creating a new cluster. My current plan is to have 2 servers, each installed on top of a ZFS10 setup (2 mirrored vdevs) and then setup ZFS replication with a fairly short replication cycle. I don't need true high availability so I don't need quorum. I just need the ability to migrate between the 2 hosts quickly, and start the VM on the other host if it died. If I end up wanting quorum, I will just add a witness node to the cluster.

I have 2 questions with the above setup:

1. If I was to manually trigger a live migration, would it only copy the differential between the last replication and the current running VM disk?
2. Do you foresee any problems with this design?

1. yes
2. without a third node (or qdevice), if one of the two nodes goes down the other will become read-only (no start/stop/config changes/.. possible, already running guests will continue to run of course)