doc: Document cephfs mirroring multi-thread

Fixes: https://tracker.ceph.com/issues/73452
Signed-off-by: Kotresh HR <khiremat@redhat.com>

diff --git a/doc/cephfs/cephfs-mirroring.rst b/doc/cephfs/cephfs-mirroring.rst
index 1283aea4493031f349bcac178492a56c9ad6f4d2..57de027f0c56a1a2eafb0ce816723fddcbe1ca9f 100644 (file)
--- a/doc/cephfs/cephfs-mirroring.rst
+++ b/doc/cephfs/cephfs-mirroring.rst
@@ -573,3 +573,14 @@ in the command output). Also, it is recommended to purge synchronized directorie
 from the peer  before re-adding it to another file system (especially those directories
 which might exist in the new primary file system). This is not required if re-adding
 a peer to the same primary file system it was earlier synchronized from.
+
+Multi-threaded snapshot sync
+----------------------------
+
+CephFS mirroring now utilizes a multi-threaded architecture to improve synchronization
+performance. The workload is split into two distinct thread pools: a crawler thread pool, which
+manages snapshot crawl and a data synchronization thread pool, which handles concurrent file
+transfers. Users can fine-tune these operations using configuration parameters:
+- ``cephfs_mirror_max_concurrent_directory_syncs``: controls the number of concurrent snapshots being crawled.
+- ``cephfs_mirror_max_concurrent_data_sync_threads``: controls the total threads available for data sync.
+For more information, see https://tracker.ceph.com/issues/73452