doc/rados: link to pg setting commands

Link to the instructions for manually setting the number of PGs per
pool, from the mention of placement groups. These instructions are
included here in response to a request from Ronen Friedman on the
occasion of the removal of links to the PGcalc (see
https://github.com/ceph/ceph/pull/55899#pullrequestreview-1912940118).

Signed-off-by: Zac Dover <zac.dover@proton.me>
(cherry picked from commit 9da81b87ca161370c869b49f5d4e6b50edd54a0e)

diff --git a/doc/rados/operations/pools.rst b/doc/rados/operations/pools.rst
index 14c0f996579828b0e2d14427e05448897e77e9e0..5501fe1a0addf8e807d44f8b3244e222f9f09a7d 100644 (file)
--- a/doc/rados/operations/pools.rst
+++ b/doc/rados/operations/pools.rst
@@ -25,7 +25,10 @@ Pools provide:
   resources. When setting up multiple pools, set an appropriate number of PGs
   for each pool and for the cluster as a whole. Each PG belongs to a specific
   pool: when multiple pools use the same OSDs, make sure that the **sum** of PG
-  replicas per OSD is in the desired PG-per-OSD target range. 
+  replicas per OSD is in the desired PG-per-OSD target range. See :ref:`Setting
+  the Number of Placement Groups <setting the number of placement groups>` for
+  instructions on how to manually set the number of placement groups per pool
+  (this procedure works only when the autoscaler is not used).
 
 - **CRUSH Rules**: When data is stored in a pool, the placement of the object
   and its replicas (or chunks, in the case of erasure-coded pools) in your