Merge PR #31729 into master

* refs/pull/31729/head:
	qa: reduce cache size further
	mds: obsoleting 'mds_cache_size'

Reviewed-by: Patrick Donnelly <pdonnell@redhat.com>

diff --cc PendingReleaseNotes
Simple merge

diff --cc doc/cephfs/mds-config-ref.rst
Simple merge

diff --cc src/common/options.cc
Simple merge

diff --cc src/mds/MDSRank.cc
Simple merge

diff --cc src/vstart.sh
Simple merge