doc/rados/operations/health-checks: Added Stretch Mode health warnings

Added stretch mode health warnings in docs for:

1. INCORRECT_NUM_BUCKETS_STRETCH_MODE

2. UNEVEN_WEIGHTS_STRETCH_MODE

Signed-off-by: Kamoltat <ksirivad@redhat.com>
(cherry picked from commit cfc415c0d95c2531c4f75dd215705f6bf3290b86)

diff --git a/doc/rados/operations/health-checks.rst b/doc/rados/operations/health-checks.rst
index b97d4d64b1ffddec0777a0b8c677cbeaef2ab897..7eaa31a5688583a95fb47887b2806549c75728ac 100644 (file)
--- a/doc/rados/operations/health-checks.rst
+++ b/doc/rados/operations/health-checks.rst
@@ -1406,6 +1406,31 @@ other performance issue with the OSDs.
 The exact size of the snapshot trim queue is reported by the ``snaptrimq_len``
 field of ``ceph pg ls -f json-detail``.
 
+Stretch Mode
+------------
+
+INCORRECT_NUM_BUCKETS_STRETCH_MODE
+__________________________________
+
+Stretch mode currently only support 2 dividing buckets with OSDs, this warning suggests
+that the number of dividing buckets is not equal to 2 after stretch mode is enabled.
+You can expect unpredictable failures and MON assertions until the condition is fixed.
+
+We encourage you to fix this by removing additional dividing buckets or bump the
+number of dividing buckets to 2.
+
+UNEVEN_WEIGHTS_STRETCH_MODE
+___________________________
+
+The 2 dividing buckets must have equal weights when stretch mode is enabled.
+This warning suggests that the 2 dividing buckets have uneven weights after
+stretch mode is enabled. This is not immediately fatal, however, you can expect
+Ceph to be confused when trying to process transitions between dividing buckets.
+
+We encourage you to fix this by making the weights even on both dividing buckets.
+This can be done by making sure the combined weight of the OSDs on each dividing
+bucket are the same.
+
 Miscellaneous
 -------------