Hi Christian In my experience, inconsistent PGs are almost always related back to a bad drive somewhere. They are going to keep happening, and with that many drives you still need to be diligent/aggressive in dropping bad drives and replacing them.
If a drive returns an incorrect read, it can't be trusted from that point. Deep scrubs just serve to churn your bits and make sure you catch these errors early on. /Chris -----Original Message----- From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of Christian Eichelmann Sent: Monday, 11 May 2015 4:10 PM To: ceph-users@lists.ceph.com Subject: [ceph-users] Scrub Error / How does ceph pg repair work? Hi all! We are experiencing approximately 1 scrub error / inconsistent pg every two days. As far as I know, to fix this you can issue a "ceph pg repair", which works fine for us. I have a few qestions regarding the behavior of the ceph cluster in such a case: 1. After ceph detects the scrub error, the pg is marked as inconsistent. Does that mean that any IO to this pg is blocked until it is repaired? 2. Is this amount of scrub errors normal? We currently have only 150TB in our cluster, distributed over 720 2TB disks. 3. As far as I know, a "ceph pg repair" just copies the content of the primary pg to all replicas. Is this still the case? What if the primary copy is the one having errors? We have a 4x replication level and it would be cool if ceph would use one of the pg for recovery which has the same checksum as the majority of pgs. 4. Some of this errors are happening at night. Since ceph reports this as a critical error, our shift is called and wake up, just to issue a single command. Do you see any problems in triggering this command automatically via monitoring event? Is there a reason why ceph isn't resolving these errors itself when it has enought replicas to do so? Regards, Christian _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
