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Upgrade from 3.x to 4.0 without downtime?


minimos
8 Posts
September 8, 2025, 6:38 am

Is it possible to upgrade PetaSAN to 4.0.0 version from any 3.x without downtime for the cluster (specifically for the cluster NFS service to go down) ?
If so, from which 3.x version?

We have a PetaSAN 3.1.0 cluster, and we'd like to upgrade, but we'd delayed the operation because of this.
Should we go though all intermediate version 3.1 -> 3.2 -> 3.3 -> 4.0 ?

Upgrade Guide document doesn't really say much other than instructing on the command to be used.

Thanks

#1

Ste
151 Posts
September 10, 2025, 3:38 pm

Reading the upgrade guide I would say you should go from any 3.x version up to 3.3, and then 3.3 -> 4.0.

Ste

#2

minimos
8 Posts
September 11, 2025, 7:23 am

I was looking at the Ceph versions in play, which I'd guess is the critical part of the upgrade, and this is what I found, looking as the package version in the various PetaSAN releases:
petasan 3.1 -> ceph 15.2.14
petasan 3.2.1 -> ceph 17.2.5
petasan 3.3.0 -> ceph 17.2.7-1petasan
petasan 4.0.0 -> ceph 18.2.4.-1petasan

So, my guess is that the upgrade 3.1 -> 3.2.1 is quite critical, as it jumps even over one major Ceph release (Octopus 15 -> Quincy 17)
and then in second order also the upgrade 3.2/3.3 to 4.0 requires attention.

I think only way to get some answers is by building a mini-cluster using VMs and seeing how it will behave with the upgrade.

Last edited on September 11, 2025, 7:25 am by minimos · #3

admin
3,054 Posts
September 13, 2025, 1:13 pm

Upgrade from Ceph 15 to 17 is allowed in Ceph ( 2 version diff is allowed )

There should not be downtime, the services such as OSDs do restart, i/o could stall for 30 sec,

#4