os/bluestore: Add documentation for large bluefs log recovery

Adds additional paragraph to ceph-bluestore-tool documentation,
describing how to use *special* options --bluefs_replay_recovery
and --bluefs_replay_recovery_disable_compact to recover large
bluefs log.

Fixes: https://tracker.ceph.com/issues/46552
Signed-off-by: Adam Kupczyk <akupczyk@redhat.com>

diff --git a/doc/man/8/ceph-bluestore-tool.rst b/doc/man/8/ceph-bluestore-tool.rst
index b18f7bc51a946a2ebdf97ddbc7a5c76f3552e68c..9f7fc56d802a503561aa34ebb69a62502595dc9c 100644 (file)
--- a/doc/man/8/ceph-bluestore-tool.rst
+++ b/doc/man/8/ceph-bluestore-tool.rst
@@ -177,6 +177,21 @@ BlueStore OSD with the *prime-osd-dir* command::
 
   ceph-bluestore-tool prime-osd-dir --dev *main device* --path /var/lib/ceph/osd/ceph-*id*
 
+BlueFS log rescue
+=====================
+
+Some versions of BlueStore were susceptible to BlueFS log growing extremaly large -
+beyond the point of making booting OSD impossible. This state is indicated by
+booting that takes very long and fails in _replay function.
+
+This can be fixed by::
+  ceph-bluestore-tool fsck --path *osd path* --bluefs_replay_recovery=true
+
+It is advised to first check if rescue process would be successfull::
+  ceph-bluestore-tool fsck --path *osd path* \
+  --bluefs_replay_recovery=true --bluefs_replay_recovery_disable_compact=true
+
+If above fsck is successfull fix procedure can be applied.
 
 Availability
 ============