LAB: Ceph EC


Active Member
Jul 2, 2010
So I'm playing around with Ceph in a lab setup on some extremely low-end hardware, and I was testing EC on a 3 node cluster.

I had Proxmox installed on USB sticks as originally, I didn't realise the OSD can be a partition rather than the whole disk.

I started removing/replacing OSD's so I could move Swap onto the SSD rather than the USB stick
What I've noticed with one OSD down, is a number of PG's go into active+undersized or active+underside+degraded and I/O is blocked, is this as expected?
running K=2,M=1, only 3 OSD's as these are SFF machines so can't take more drives.
It seems since yesterday there's been a CEPH update, I just upgraded from 17.2.4 to 17.2.5 and now I seem to be able to write to the EC 2,1 volumes with a OSD offline.

I think it was actually the lack of Trim and the state of some of my SSD's that was the problem and it working after upgrade was just a co-incidence
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