doc/src: edit osd.yaml.in (osd_deep_scrub_interval_cv)

Improve the English in the "desc" field of the
"osd_deep_scrub_interval_cv" variable, as suggested by Anthony D'Atri in
https://github.com/ceph/ceph/pull/63490#discussion_r2124893516.

Signed-off-by: Zac Dover <zac.dover@proton.me>
(cherry picked from commit 32cd44300882947310d2419279fe7f950ddac17b)

diff --git a/src/common/options/osd.yaml.in b/src/common/options/osd.yaml.in
index 90b97d91f20760ddb5b029b76736ef053827e07d..c25d138932cbd8f76d24612c9993a757ff6ce644 100644 (file)
--- a/src/common/options/osd.yaml.in
+++ b/src/common/options/osd.yaml.in
@@ -502,6 +502,25 @@ options:
     ``osd_scrub_load_threshold`` does not affect this setting.
   default: 7_day
   with_legacy: true
+- name: osd_deep_scrub_interval_cv
+  type: float
+  level: advanced
+  desc: Determines the amount of variation in the deep scrub interval
+  long_desc: Deep scrub intervals are varied by a random amount to prevent
+    stampedes. This parameter determines the amount of variation.
+    Technically ``osd_deep_scrub_interval_cv`` is the coefficient of variation for
+    the deep scrub interval.
+  fmt_desc: The coefficient of variation for the deep scrub interval, specified as a
+    ratio. On average, the next deep scrub for a PG is scheduled osd_deep_scrub_interval
+    after the last deep scrub . The actual time is randomized to a normal distribution
+    with a standard deviation of osd_deep_scrub_interval * osd_deep_scrub_interval_cv
+    (clamped to within 2 standard deviations).
+    The default value guarantees that 95% of deep scrubs will be scheduled in the range
+    [0.8 * osd_deep_scrub_interval, 1.2 * osd_deep_scrub_interval].
+  min: 0
+  max: 0.4
+  default: 0.2
+  with_legacy: false
 - name: osd_deep_scrub_randomize_ratio
   type: float
   level: advanced