Add an entry for "OMAP" to the glossary. This commit represents only the
first improvement to the documentation of OMAP in the Ceph docs suite.
Signed-off-by: Zac Dover <zac.dover@proton.me>
Object Storage Device
See :term:`OSD`.
+ OMAP
+ "object map". A key-value store (a database) that is used to
+ reduce the time it takes to read data from and to write to the
+ Ceph cluster. RGW bucket indexes are stored as OMAPs.
+ Erasure-coded pools cannot store RADOS OMAP data structures.
+
+ Run the command ``ceph osd df`` to see your OMAPs.
+
+ See Eleanor Cawthon's 2012 paper `A Distributed Key-Value Store
+ using Ceph
+ <https://ceph.io/assets/pdfs/CawthonKeyValueStore.pdf>`_ (17
+ pages).
+
OSD
Probably :term:`Ceph OSD`, but not necessarily. Sometimes
(especially in older correspondence, and especially in