doc: add the reject the clone when threads are not available feature in the document

Fixes: https://tracker.ceph.com/issues/59714
Signed-off-by: Neeraj Pratap Singh <neesingh@redhat.com>
(cherry picked from commit 6a44322d59e5542731dd450b383046a13bc28a66)

Conflicts:
	doc/cephfs/fs-volumes.rst: order of lines were improper
	due to amendments in `max_concurrent_clones` config option
	explanation.

diff --git a/PendingReleaseNotes b/PendingReleaseNotes
index 5dfea2b42ce83e6b2eb55f08155c9c1b12b9df9d..2323d8aed6ce155d906d31fe60bc16f481ca13d2 100644 (file)
--- a/PendingReleaseNotes
+++ b/PendingReleaseNotes
@@ -90,6 +90,15 @@
 * CephFS: Full support for subvolumes and subvolume groups is now available
   for snap_schedule Manager module.
 
+* CephFS: The `subvolume snapshot clone` command now depends on the config option
+  `snapshot_clone_no_wait` which is used to reject the clone operation when
+  all the cloner threads are busy. This config option is enabled by default which means 
+  that if no cloner threads are free, the clone request errors out with EAGAIN.
+  The value of the config option can be fetched by using:
+   `ceph config get mgr mgr/volumes/snapshot_clone_no_wait`
+  and it can be disabled by using:
+   `ceph config set mgr mgr/volumes/snapshot_clone_no_wait false`
+
 >=18.0.0
 
 * The RGW policy parser now rejects unknown principals by default. If you are

diff --git a/doc/cephfs/fs-volumes.rst b/doc/cephfs/fs-volumes.rst
index e7fd377bf735833cf2eb3fba11785ed59cc1e8bb..0dc783d583d0aacfd6e6608324cb8fee7a9d91ca 100644 (file)
--- a/doc/cephfs/fs-volumes.rst
+++ b/doc/cephfs/fs-volumes.rst
@@ -501,10 +501,14 @@ To initiate a clone operation use::
 
   $ ceph fs subvolume snapshot clone <vol_name> <subvol_name> <snap_name> <target_subvol_name>
 
+.. note:: ``subvolume snapshot clone`` command depends upon the above mentioned config option ``snapshot_clone_no_wait``
+
 If a snapshot (source subvolume) is a part of non-default group, the group name needs to be specified::
 
   $ ceph fs subvolume snapshot clone <vol_name> <subvol_name> <snap_name> <target_subvol_name> --group_name <subvol_group_name>
 
+If a snapshot (source subvolume) is a part of non-default group, the group name needs to be specified:
+
 Cloned subvolumes can be a part of a different group than the source snapshot (by default, cloned subvolumes are created in default group). To clone to a particular group use::
 
   $ ceph fs subvolume snapshot clone <vol_name> <subvol_name> <snap_name> <target_subvol_name> --target_group_name <subvol_group_name>
@@ -513,13 +517,15 @@ Similar to specifying a pool layout when creating a subvolume, pool layout can b
 
   $ ceph fs subvolume snapshot clone <vol_name> <subvol_name> <snap_name> <target_subvol_name> --pool_layout <pool_layout>
 
-Configure the maximum number of concurrent clones. The default is 4::
+To check the status of a clone operation use::
 
-  $ ceph config set mgr mgr/volumes/max_concurrent_clones <value>
+   ceph fs subvolume snapshot clone <vol_name> <subvol_name> <snap_name> <target_subvol_name> --pool_layout <pool_layout>
 
-To check the status of a clone operation use::
+To check the status of a clone operation use:
 
-  $ ceph fs clone status <vol_name> <clone_name> [--group_name <group_name>]
+.. prompt:: bash #
+
+   ceph fs clone status <vol_name> <clone_name> [--group_name <group_name>]
 
 A clone can be in one of the following states:
 
@@ -616,6 +622,29 @@ On successful cancellation, the cloned subvolume is moved to the ``canceled`` st
 
 .. note:: The canceled cloned may be deleted by supplying the ``--force`` option to the `fs subvolume rm` command.
 
+Configurables
+~~~~~~~~~~~~~
+
+Configure the maximum number of concurrent clone operations. The default is 4:
+
+.. prompt:: bash #
+
+   ceph config set mgr mgr/volumes/max_concurrent_clones <value>
+
+Configure the snapshot_clone_no_wait option :
+
+.. prompt:: bash #
+
+   ``snapshot_clone_no_wait`` config option is used to reject the clone creation request when the cloner threads 
+   ( which can be configured using above option i.e. ``max_concurrent_clones``) are not available.
+   It is enabled by default i.e. the value set is True, whereas it can be configured by using below command.
+
+   ceph config set mgr mgr/volumes/snapshot_clone_no_wait <bool>
+
+   The current value of ``snapshot_clone_no_wait`` can be fetched by using below command.
+
+   ceph config get mgr mgr/volumes/snapshot_clone_no_wait
+
 
 .. _subvol-pinning: