diff --git a/scst/README b/scst/README
index c25f5df7d..b5bd7c81d 100644
--- a/scst/README
+++ b/scst/README
@@ -1106,7 +1106,8 @@ with files with names the same as the names of the corresponding
 devices. Also this directory contains backup versions of those files
 with suffix ".1". Those backup files are used in case of power or other
 failure to prevent Persistent Reservation information from corruption
-during update.
+during update. It is safe to assume that each of those files can be up
+to 1KB big.
 
 The "Persistence Through Power Loss" feature is not available in the
 procfs build, because the SCST proc interface doesn't allow to keep
diff --git a/scst/README_in-tree b/scst/README_in-tree
index be1f1baf6..34106b220 100644
--- a/scst/README_in-tree
+++ b/scst/README_in-tree
@@ -964,7 +964,8 @@ with files with names the same as the names of the corresponding
 devices. Also this directory contains backup versions of those files
 with suffix ".1". Those backup files are used in case of power or other
 failure to prevent Persistent Reservation information from corruption
-during update.
+during update. It is safe to assume that each of those files can be up
+to 1KB big.
 
 The Persistent Reservations available on all transports implementing
 get_initiator_port_transport_id() callback. Transports not implementing