From 1b656450ca75b12fb98dee82bace914ef5f45c44 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Tue, 23 Sep 2014 16:21:33 -0700 Subject: [PATCH] osd: initialize purged_snap on backfill start; restart backfill if change If we backfill a PG to a new OSD, we currently neglect to initialize purged_snaps. As a result, the first time the snaptrimmer runs it has to churn through every deleted snap for all time, and to make matters worse does so in one go with the PG lock held. This leads to badness on any cluster with a significant number of removed snaps that experiences backfill. Resolve this by initializing purged_snaps when we finish backfill. The backfill itself will clear out any stray snaps and ensure the object set is in sync with purged_snaps. Note that purged_snaps on the primary that is driving backfill will not change during this period as the snaptrimmer is not scheduled unless the PG is clean (which it won't be during backfill). If we by chance to interrupt backfill, go clean with other OSDs, purge snaps, and then let this OSD rejoin, we will either restart backfill (non-contiguous log) or the log will include the result of the snap trim (the events that remove the trimmed snap). Fixes: #9487 Backfill: firefly, dumpling Signed-off-by: Sage Weil (cherry picked from commit 255b430a87201c7d0cf8f10a3c1e62cbe8dd2d93) --- src/osd/PG.cc | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/osd/PG.cc b/src/osd/PG.cc index 6cabdb7eb0028..ebc2020cfff27 100644 --- a/src/osd/PG.cc +++ b/src/osd/PG.cc @@ -1553,6 +1553,9 @@ void PG::activate(ObjectStore::Transaction& t, pi.hit_set = info.hit_set; pi.stats.stats.clear(); + // initialize peer with our purged_snaps. + pi.purged_snaps = info.purged_snaps; + m = new MOSDPGLog( i->shard, pg_whoami.shard, get_osdmap()->get_epoch(), pi); -- 2.39.5