ameet009
Contributor
Contributor

VSAN Add more hosts

Hello, I m planning to add 3 more hosts to my current vsan cluster( currently 5 hosts) and it will be total 8 after adding it.

few questions..

can I just add them directly to the cluster and then configure it with DV switch ports /vmotion/nfs etc for new hosts or any downtime issue?

current FTT-2 .. after adding 3 more hosts can i change FTT to 3?

4 Replies

Hi amet,

Yes you can add the host while everything is running without any issue. As you mentioned, add the host to the cluster, configure the networking, vsan and thats it.

You can also use the ftt3 policy (But be carefull if you are going to change the default policy or the policy that all the vms are using. I would suggest that you create a new policy and start moving the vms to analize permormance impacts)

Cheers

N

-------------------------------------------------------------------
Triple VCIX (CMA-NV-DCV) | vExpert | MCSE | CCNA
ameet009
Contributor
Contributor

Thank you Nicolas! I will try same .

0 Kudos
TheBobkin
VMware Employee
VMware Employee

Hello ameet009​,

Welcome to Communities,

As Nicolas said, it is just a case of 'drag-and'drop' and configuring the necessary functions - vSAN Health will aid in validating some (but not all) of the possible things that could be misconfigured in doing this.

From the fact that you mentioned that you are running a 5-node cluster currently this indicate that you are running FTM=RAID1,FTT=2 (as minimum is 6-node for FTM=RAID6), thus adding more nodes and changing the to FTM=RAID1,FTT=3 will essentially just create an extra mirror (and and extra witness component) on the new nodes (and not result in a 'deep-reconfig' of all data as it would if for instance changing from RAID5/6 to RAID1).

More to the point though, can you tell us some of your design justifications as to why you are considering (from the way you have phrased your query) running FTM=RAID1,FTT=3?

The vast majority of vSAN customers run FTT=1 and a portion FTT=2 and then in addition to this go with the more modern design decisions of redundancy at depth (e.g. failover sites, in-guest clustering, application-level redundancy and load-balancing).

If you are also doing these things here and just want some extra fault tolerance in a priority cluster that is fine, but if not then do consider that designing any infrastructure should never be just about one cluster.

Bob

0 Kudos
depping
Leadership
Leadership

Fully agree with the above. We barely have ANY customers doing FTT=3, mainly because of the cost implication. If you have an availability requirements, make the change you need, but if there's no direct requirement I would rethink it. FTT=2 appears to be the sweetspot for most of our customers at this point.

0 Kudos