ChevUribe
Expert
Expert

VSAN inquiries

1. If I enable HA/DRS on a VSAN cluster, no restart from the existing hosts and virtual machines will happen during activation?

2. I have a 8 node VSAN cluster, what is recommended FTT=1 or 2? Client is very particular on storage capacity and usage.

3. If I have to change FTT, will there be any downtime to the hosts and existing virtual machines? How can I change the FTT settings?

2 Replies
zdickinson
Expert
Expert

Good morning.

1. If I enable HA/DRS on a VSAN cluster, no restart from the existing hosts and virtual machines will happen during activation?

There will be no restart of hosts or VMs when enabling HA/DRS.

2. I have a 8 node VSAN cluster, what is recommended FTT=1 or 2? Client is very particular on storage capacity and usage.

With 8 nodes, assuming they are all contributing storage, I would go with FTT=2

3. If I have to change FTT, will there be any downtime to the hosts and existing virtual machines? How can I change the FTT settings?

There is no downtime to change FTT.  You could either change the policy that is applied to VMs or create a new policy and apply that.

Hope that helps, Zach.

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kelwood
Enthusiast
Enthusiast

I would note on #2 that it depends on the concerns of the client. You say they are particular on storage capacity and usage but didn't mention their concern with data loss. With FTT=2 you can lose two copies of the data and still be okay but depending on the version of vSAN and whether you are going AF or Hybrid you may use 3x the actual data ie. 100GB of used data consumes 300GB of the available vSAN datastore. If your client will be upset buying 30TB of storage and only getting to allocate 10TB than FTT=2 is not the way to go but if they don't mind that and would hate to suffer two failures and lose everything than FTT=2 is best. Remember that FTT level can be set differently for each machine so you can change depending on how critical that VM is.