Remote backup stuck rebuilding - deltas are protected, what happens at failure

[steez]

Hello everyone,

I need a bit of an in-depth advice on Simplivity remote backup behavior. This one will be hard to grasp so brace yourselves

We have 2 SVT clusters. We are migrating VMs from the old to the new as we plan to decomission the old cluster. For all VMs we used VMware Live migration with some hiccups but 99% of VMs are in the new cluster.

We have an issue with the very last VM in our environment that is large in terms of storage and memory usage. As its data is changing not stop we suspect that the network wont be able to keep up and live-migration will fail (had this with some other VMs but found some windows where they were less active).

In oder to get around this we plan to use Simplvity Remote backp (do initial backup, then turn off VM, do delta backup, restore at the new cluster). With this we have an issue - after initial remote backup, the backup state changes from saving to rebuilding and is stuck there (for 3 weeks now, sent size 3TB). As per HPE documentation, rebulding means that backup itself is not HA protected at this moment and backup data is being duplicated with another host in cluster to make it HA. Interestingly the subsequent backups sometimes go to degraded or protected state.

After working with HPE support (event escalating from L3 to LAB), they said that this is a software defect with a suggestion to still restore VM from subsequent protected backup, but I have my doubts with this so I have a question about how remote backups work and behave in case of a failure.

As subsequent backups are much smaller in size (about 10x in our case) I assume that they create a chain with initial backup (which I remind is in degraded state). What happens I restore VM from protected subsequent backup and the host that has non-HA initial backup fails? Will the VM also fail?

Asked HPE support about this for which they answered - should have identical data as the original VM (assuming no data change has been made on the original VM since the backup has taken place which the question was not about.

This is a hard concept to grasp, but really hope for Simplivity Guru/design architect to stumble accross this post and shine some light to this. In any case we will try to move VM to the new cluster using Veeam Replication (still far from ideal as VMware snapshots will be used with memory-storage active VM.