doc/rados/operations: Strengthen cache-tiering deprecation notice

The existing warning hedged with "this does not mean it will certainly
be removed", softening the message for a deprecated feature. Operators
scanning the page may begin a how-to setup without reading past the
introductory prose.

- Remove the hedging language; state plainly that cache tiering may be
  removed without further notice
- Add a bold "Do not deploy new cache tiers" directive
- Add a note immediately before the how-to content scoping the page
  to existing deployments only, with a pointer to preferred alternatives

Fixes: https://tracker.ceph.com/issues/77184
Signed-off-by: Emmanuel Ameh <eameh@contractor.linuxfoundation.org>

diff --git a/doc/rados/operations/cache-tiering.rst b/doc/rados/operations/cache-tiering.rst
index f9edf936fb80f75a50f41bc1d4a454402db8d7db..a1f8e49a933b86a4b08477d348d64f504208ccf5 100644 (file)
--- a/doc/rados/operations/cache-tiering.rst
+++ b/doc/rados/operations/cache-tiering.rst
@@ -2,14 +2,16 @@
  Cache Tiering
 ===============
 
-.. warning:: Cache tiering has been deprecated in the Reef release. Cache
-   tiering has lacked a maintainer for a long time. This does not mean that
-   it will certainly be removed, but it might be removed without much
-   notice.
-
-   The upstream Ceph community strongly advises against deploying new cache
-   tiers. The upstream Ceph community also recommends migrating from legacy
-   deployments.
+.. warning:: Cache tiering was deprecated in the Reef release and has lacked
+   a maintainer for a long time. It will be removed in a future release without
+   notice. **Do not deploy new cache tiers.** Migrate existing cache
+   tier deployments as soon as possible.
+
+.. note:: The following documentation is retained for reference for existing
+   deployments only. For new deployments, use erasure-coded pools or fast
+   storage pools directly. As a community-supported block-level caching
+   alternative, consider ``dm-cache`` (the Linux kernel's device-mapper cache
+   target).
 
 A cache tier provides Ceph clients with better I/O performance for a subset of
 the data stored in a backing storage tier. Cache tiering involves creating a