doc/cephfs: Add note how mds_max_snaps_per_dir affects snapshot retention

Signed-off-by: Jakob Haufe <sur5r@sur5r.net>
(cherry picked from commit 2e8af66ed4678775a3f686738c12ac04abfd770e)

diff --git a/doc/cephfs/snap-schedule.rst b/doc/cephfs/snap-schedule.rst
index fb9c85b5a44c537e70d5360d5e8173b0af5eab28..70efe2547f10cf6702a76ddfac58945d62569f41 100644 (file)
--- a/doc/cephfs/snap-schedule.rst
+++ b/doc/cephfs/snap-schedule.rst
@@ -155,6 +155,11 @@ Examples::
    snapshot creation is accounted for in the "created_count" field, which is a
    cumulative count of the total number of snapshots created so far.
 
+.. note: The maximum number of snapshots to retain per directory is limited by the
+   config tunable `mds_max_snaps_per_dir`. This tunable defaults to 100.
+   To ensure a new snapshot can be created, one snapshot less than this will be
+   retained. So by default, a maximum of 99 snapshots will be retained.
+
 Active and inactive schedules
 -----------------------------
 Snapshot schedules can be added for a path that doesn't exist yet in the