Using system lock on file systems

File Service Administration Guide for Hitachi NAS Platform

Version
14.9.x
Audience
anonymous
Part Number
MK-92HNAS006-31
System Lock mode protects file systems during replication and transfer of primary access operations. Four important distinctions apply:
  • NDMP (Network Data Management Protocol) versus file service protocols. When System Lock is enabled for a file system:
    • NDMP has full access (including writes) during backups, replication, and transfer of primary access.
    • The file system remains in read-only mode to clients using the file service protocols (NFS, CIFS, FTP, and iSCSI).
  • System Lock versus read only:
    • When a file system is Syslocked, NDMP still has full access to that file system and can write to it.
    • When a file system is mounted as read-only, NDMP (like all other protocols) has read-only access to that file system, and cannot write to it. To ensure that a file system remains completely unchanged, you should mount it as read-only.
  • Replication versus transfer of primary access:
    • During replication operations, the destination file system is put into System Lock mode.
    • During transfer of primary access operations, both the source file system and the destination file system are put into System Lock mode.
  • Read Cache Exception. A read cache may not be put into System Lock mode.