[ceph-users] Re: damaged cephfs

Hi there, we reconfigured our ceph cluster yesterday to remove the cluster network and things didn't quite go to plan. I am trying to figure out what went wrong and also what to do next. We are running nautilus 14.2.10 on Scientific Linux 7.8. So, we are using a mixture of RBDs and cephfs. For the transition we switched off all machines that are using the RBDs and switched off the cephfs using ceph fs set one down true Once no more MDS were running we reconfigured ceph to remove the cluster network and set various flags ceph osd set noout ceph osd set nodown ceph osd set pause ceph osd set nobackfill ceph osd set norebalance ceph osd set norecover We then restarted the OSDs one host at a time. During this process ceph was mostly happy, except for two PGs. After all OSDs had been restarted we switched off the cluster network switches to make sure it was totally gone. ceph was still happy. The PG error also disappeared. We then unset all those errors and re-enabled cephfs. We then switched on the servers using the RBDs with no issues. So far so good. We then started using the cephfs (we keep VM images on the cephfs). The MDS were showing an error. I restarted the MDS but they didn't come back.We then followed the instructions here: https://docs.ceph.com/docs/nautilus/cephfs/disaster-recovery-experts/#disas… up to truncating the journal. The MDS started again. However, as soon as we started writing the cephfs the MDS crashed. A scrub of the cephfs revealed backtrace damage.

We have now followed the remaining steps of the disaster recovery procedure and are waiting for the cephfs-data-scan scan_extents to complete. It would be really helpful if you could give an indication of how long this process will take (we have ~40TB in our cephfs) and how many workers to use.

The other missing bit of documentation is the cephfs scrubbing. Is that something we should run routinely?