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| author | David Zafman <david.zafman@inktank.com> | 2013-05-07 18:03:25 -0700 |
|---|---|---|
| committer | David Zafman <david.zafman@inktank.com> | 2013-05-09 12:00:29 -0700 |
| commit | 00e903160b33fe0a2195fe9c86ed24350944bdea (patch) | |
| tree | 66bd43656d3dfcb1621f6dd3adf4054dfcd08ba9 /doc | |
| parent | 09163a3bbc37223416a87dec39dfe2db7c06d2ba (diff) | |
| download | ceph-00e903160b33fe0a2195fe9c86ed24350944bdea.tar.gz | |
osd: prioritize recovery for degraded pgs
Three Reservation priorities from RECOVERY, BACKFILL_HIGH, BACKFILL_LOW
fixes: #4273
Signed-off-by: David Zafman <david.zafman@inktank.com>
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/dev/osd_internals/backfill_reservation.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/doc/dev/osd_internals/backfill_reservation.rst b/doc/dev/osd_internals/backfill_reservation.rst index 11c92cd5472..1fa2d074147 100644 --- a/doc/dev/osd_internals/backfill_reservation.rst +++ b/doc/dev/osd_internals/backfill_reservation.rst @@ -25,3 +25,10 @@ ReplicaActive. It's important that we always grab the local reservation before the remote reservation in order to prevent a circular dependency. + +We want to minimize the risk of data loss by prioritizing the order in which +PGs are recovered. We use 3 AsyncReserver priorities to hand out reservations. +The highest priority is log based recovery (RECOVERY) since this must always +complete before backfill can start. The next priority is backfill of degraded +PGs (BACKFILL_HIGH). The lowest priority is backfill of non-degraded PGs +(BACKFILL_LOW). |