Hi Janne,
Thanks for your advice.
So, you mean with with K=4 M =2 EC, we need 8 OSD nodes to have better
protection
Thanks,
Gagan
On Tue, 22 Apr, 2025, 7:22 pm Janne Johansson, <icepic...@gmail.com> wrote:
> > So, I need to know what will be data safely level with the above set-up (
> > i.e. 6 OSDs with 4X2 EC ). How many OSDs ( disks ) and nodes failure ,
> > above set-up can withstand.
>
> With EC N+2 you can lose one drive or host, and the cluster will go on
> with degraded mode until it has been able to recreate the missing data
> on another OSD, if you lose two drives or hosts, I believe the EC pool
> with go readonly, again until it has rebuilt copies elsewhere.
>
> Still, if you have EC 4+2 and only 6 OSD hosts, this means if a host
> dies, the cluster can not recreate data anywhere without violating
> "one copy per host" default placement, so the cluster will be degraded
> until this host comes back or another one replaces it. For a N+M EC
> cluster, I would suggest having N+M+1 or even +2 number of hosts, so
> that you can do maintenance on a host or lose a host and still be able
> to recover without visiting the server room.
>
> --
> May the most significant bit of your life be positive.
>
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