doc: v0.56.2 release notes

Signed-off-by: Sage Weil <sage@inktank.com>

doc/release-notes.rst

@@ -2,6 +2,60 @@
  Release Notes
 ===============
 
+v0.56.2 "bobtail"
+-----------------
+
+This release has a wide range of bug fixes, stability improvements, and some performance improvements.  Please upgrade.
+
+Upgrading
+~~~~~~~~~
+
+* The meaning of the 'osd scrub min interval' and 'osd scrub max
+  interval' has changed slightly.  The min interval used to be
+  meaningless, while the max interval would only trigger a scrub if
+  the load was sufficiently low.  Now, the min interval option works
+  the way the old max interval did (it will trigger a scrub after this
+  amount of time if the load is low), while the max interval will
+  force a scrub regardless of load.  The default options have been
+  adjusted accordingly.  If you have customized these in ceph.conf,
+  please review their values when upgrading.
+
+* CRUSH maps that are generated by default when calling ``ceph-mon
+  --mkfs`` directly now distribute replicas across hosts instead of
+  across OSDs.  Any provisioning tools that are being used by Ceph may
+  be affected, although probably for the better, as distributing across
+  hosts is a much more commonly sought behavior.  If you use
+  ``mkcephfs`` to create the cluster, the default CRUSH rule is still
+  inferred by the number of hosts and/or racks in the initial ceph.conf.
+
+Notable changes
+~~~~~~~~~~~~~~~
+
+* osd: snapshot trimming fixes
+* osd: scrub snapshot metadata
+* osd: fix osdmap trimming
+* osd: misc peering fixes
+* osd: stop heartbeating with peers if internal threads are stuck/hung
+* osd: PG removal is friendlier to other workloads
+* osd: fix recovery start delay (was causing very slow recovery)
+* osd: fix scheduling of explicitly requested scrubs
+* osd: fix scrub interval config options
+* osd: improve recovery vs client io tuning
+* osd: improve 'slow request' warning detail for better diagnosis
+* osd: default CRUSH map now distributes across hosts, not OSDs
+* osd: fix crash on 32-bit hosts triggered by librbd clients
+* librbd: fix error handling when talking to older OSDs
+* mon: fix a few rare crashes
+* ceph command: ability to easily adjust CRUSH tunables
+* radosgw: object copy does not copy source ACLs
+* rados command: fix omap command usage
+* sysvinit script: set ulimit -n properly on remote hosts
+* msgr: fix narrow race with message queuing
+* fixed compilation on some old distros (e.g., RHEL 5.x)
+
+For more detailed information, see :download:`the complete changelog <changelog/v0.56.2.txt>`.
+
+
 v0.56.1 "bobtail"
 -----------------