diff --git a/doc/common/tables/cinder-backups_nfs.xml b/doc/common/tables/cinder-backups_nfs.xml
index c86f9c9278..a1e036a4c2 100644
--- a/doc/common/tables/cinder-backups_nfs.xml
+++ b/doc/common/tables/cinder-backups_nfs.xml
@@ -27,7 +27,7 @@
       </tr>
       <tr>
         <td><option>backup_file_size</option> = <replaceable>1999994880</replaceable></td>
-        <td>(IntOpt) The maximum size in bytes of the files used to hold backups. If the volume being backed up exceeds this size, then it will be backed up into multiple files.</td>
+        <td>(IntOpt) The maximum size in bytes of the files used to hold backups. If the volume being backed up exceeds this size, then it will be backed up into multiple files. backup_file_size must be a multiple of backup_sha_block_size_bytes.</td>
       </tr>
       <tr>
         <td><option>backup_mount_options</option> = <replaceable>None</replaceable></td>
@@ -39,7 +39,7 @@
       </tr>
       <tr>
         <td><option>backup_sha_block_size_bytes</option> = <replaceable>32768</replaceable></td>
-        <td>(IntOpt) The size in bytes that changes are tracked for incremental backups. backup_swift_object_size has to be multiple of backup_swift_block_size.</td>
+        <td>(IntOpt) The size in bytes that changes are tracked for incremental backups. backup_file_size has to be multiple of backup_sha_block_size_bytes.</td>
       </tr>
       <tr>
         <td><option>backup_share</option> = <replaceable>None</replaceable></td>