[PATCH proxmox-backup 8/9] docs: add explanation regarding ``rebuild-chunk-markers`` option

[Shan Shaji <s.shaji@proxmox.com>]

Signed-off-by: Shan Shaji <s.shaji@proxmox.com>
---
 docs/storage.rst | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/docs/storage.rst b/docs/storage.rst
index 2c6ba0a85..811b5ff44 100644
--- a/docs/storage.rst
+++ b/docs/storage.rst
@@ -312,8 +312,11 @@ To setup a new datastore called ``my-s3-store`` placed in a bucket called ``pbs-
 A datastore cannot be shared between multiple Proxmox Backup Server instances, only one instance can
 operate on the datastore at a time. However, datastore contents used on an instance which is no
 longer available can be reused on a fresh installation. To recreate the datastore, you must pass the
-``reuse-datastore`` and ``overwrite-in-use`` flags. Since the datastore name is used as prefix, the
-same datastore name must be used.
+``reuse-datastore`` and ``overwrite-in-use`` flags. The optional ``rebuild-chunk-markers`` flag,
+disabled by default, creates local zero-byte chunk markers when reusing an S3 datastore. These markers
+allow Proxmox Backup Server to identify chunks already stored in S3 when they are not present in
+the in-memory cache, avoiding unnecessary uploads. The time required to create these markers depends
+on the number of chunks.
 
 .. code-block:: console
 
-- 
2.47.3