Hi, I'm not sure for krbd, but with librbd, using trim/discard on the client,
don't do trim/discard on the osd physical disk. It's simply write zeroes in the rbd image. zeores write can be skipped since this commit (librbd related) https://github.com/xiaoxichen/ceph/commit/e7812b8416012141cf8faef577e7b27e1b29d5e3 +OPTION(rbd_skip_partial_discard, OPT_BOOL, false) Then you can still manage fstrim manually on the osd servers ----- Mail original ----- De: "Chad William Seys" <cws...@physics.wisc.edu> À: "ceph-users" <ceph-us...@ceph.com> Envoyé: Samedi 22 Août 2015 04:26:38 Objet: [ceph-users] TRIM / DISCARD run at low priority by the OSDs? Hi All, Is it possible to give TRIM / DISCARD initiated by krbd low priority on the OSDs? I know it is possible to run fstrim at Idle priority on the rbd mount point, e.g. ionice -c Idle fstrim -v $MOUNT . But this Idle priority (it appears) only is within the context of the node executing fstrim . If the node executing fstrim is Idle then the OSDs are very busy and performance suffers. Is it possible to tell the OSD daemons (or whatever) to perform the TRIMs at low priority also? Thanks! Chad. _______________________________________________ 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
