Add a note to the documentation that cache tiering is deprecated in
Reef.
Signed-off-by: Zac Dover <zac.dover@proton.me>
Cache Tiering
-------------
+.. note:: Cache tiering is deprecated in Reef.
+
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
pool of relatively fast/expensive storage devices (e.g., solid state drives)
Cache Tiering
===============
+.. note:: Cache tiering is deprecated in Reef.
+
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
pool of relatively fast/expensive storage devices (e.g., solid state drives)
Erasure-coded pools and cache tiering
-------------------------------------
+.. note:: Cache tiering is deprecated in Reef.
+
Erasure-coded pools require more resources than replicated pools and
lack some of the functionality supported by replicated pools (for example, omap).
To overcome these limitations, one can set up a `cache tier <../cache-tiering>`_