src/common: add guidance for mon_warn_pg_not_scrubbed

Add an explanation of how to set the value of
"mon_warn_pg_not_scrubbed_ratio" to the confval definition of that
variable. Although this variable contains the string "mon", it is set on
the Manager. I have added a note to direct users to set this value on
the Manager.

This issue was pointed out by Petr Tlapa on Slack in late March of 2025.

This issue is part of a small project that also encompasses
https://github.com/ceph/ceph/pull/62459, which is associated with commit
aeef59a50ee31072648ba0c7436b6522137614cd

Co-authored-by: Anthony D'Atri <anthony.datri@gmail.com>
Signed-off-by: Zac Dover <zac.dover@proton.me>
(cherry picked from commit 5754906c3bd15a63855b8265a3ac93ae2a1a3c8c)

diff --git a/src/common/options/global.yaml.in b/src/common/options/global.yaml.in
index 67bcefc84bc807d2ce58b95ded482a656bc7d676..9d7cdec6bb42aadc4f3d33e5d2512f2ee3586c65 100644 (file)
--- a/src/common/options/global.yaml.in
+++ b/src/common/options/global.yaml.in
@@ -1773,7 +1773,7 @@ options:
 - name: mon_warn_pg_not_scrubbed_ratio
   type: float
   level: advanced
-  desc: Percentage of the scrub max interval past the scrub max interval to warn
+  desc: Raise a health warning when shallow scrubs are delayed by this percentage of the shallow scrub interval. Note that this must be set at mgr or with global scope. Set this configurable with the command "ceph config set mgr mon_warn_pg_not_scrubbed_ratio <ratio_value>".
   default: 0.5
   see_also:
   - osd_scrub_max_interval