We continue to talk about the operation of Ceph. Today we'll talk about the data recovery process and the flags that allow you to control it: norebalance, nobackfill and norecover.
, « ». Ceph «».
OSD.
rebuild rebalance Ceph
, rebuild rebalance, rebuild — , rebalance — .
. rebuild , , . rebalance , .
Ceph rebuild rebalance : placement group 6 . : degraded misplaced.
degraded, , - placement group . , : placement group , primary, . - , degraded. degraded — rebuild .
, placement group Ceph placement groups OSD. misplaced , . placement group , , - placement group, . , placement group Ceph . rebalance .
degraded misplaced, , rebuild, rebalance.
:
- nobackfill norecover,
- norebalance.
nobackfill norecover
nobackfill norecover . recover -, : recovery io.
.
- :
ceph osd set norecover
OSD out, recovery.
systemctl stop ceph-osd@0
ceph osd out 0
recovery, placement group. recovery io, .
.
degraded placement group, , recovery .
noout, OSD out. : norecover, recovery recovery.
norecover , , , misplaced.
:
ceph osd unset norecover
: recovery io.
nobackfill, recovery io . .
norebalance
norebalance . recovery io , placement group degraded.
norebalance:
, recovery , placement group degraded.
-.
norebalance norecover ( , ):
out OSD ( 1).
ceph osd out 1
, OSD out . , degraded placement group .
OSD 1 out. placement group OSD. — misplaced.
norecover norebalance.
misplaced, placement group degraded.
, degraded .
norecover norebalance
: . , noout.
. , - . , Ceph placement group . - ( ), . norecover, recovery io.
, , . placement group active, .
norecover, . , , . , norecover Ceph .
norebalance , . , rebalance (, ).
. recovery io , - : slow ops, . recovery io norecover, misplaced norebalance. , .
pause
pause io. , Ceph.
ceph osd set pause
, Ceph , degraded misplaced , — io, , recovery. « recovery io», .
pause , recovery io. MDS .
.
, . .
(, ), , 3-5-10 .
DDoS-. - io , . , pause.
pause: , , recovery io , .
: . . , Ceph, . . Ceph .