HP CIFS File Locking Interoperation

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8.2 EMC Celerra
EMC markets its Celerra file server as a NAS front-end to a Symetrix disk array. Celerra is
a single-purpose front-end server used exclusively for storage access to Symetrix. It runs a
proprietary OS called DART that is incapable of running applications, users, or accessing
and interoperating with non -EMC storage devices.
Since Celerra supports no users or applications, UNIX-Windows concurrent file access is not
an issue. EMC documentation about locking behavior of Celerra is vague, but basic behavior
can be surmised by utilizing various documents.
Based upon EMC documentation, Celerra provides the following file locking ability:
Mandatory Share Mode (Open Mode) EMC Celerra
Lock Windows Yes
Lock UNIX – no advisory locking Not Applicable
Lock UNIX – advisory locking Not Applicable
Lock UNIX/NFS – no advisory locking Unknown
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Lock UNIX/NFS – advisory locking Yes
Lock PC-NFS Unknown
Byte Range Locking
Lock Windows Yes
Lock UNIX – no advisory locking Not Applicable
Lock UNIX – advisory locking Not Applicable
Lock UNIX/NFS – no advisory locking Unknown
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Lock UNIX/NFS – advisory locking Yes
Lock PC-NFS Unknown
Oplocks
Break Oplock for Windows access Yes
Break Oplock for UNIX access – no
advisory
Not Applicable
Break Oplock for UNIX access - advisory Not Applicable
Break Oplock for UNIX/NFS – no advisory Unknown
Break Oplock for UNIX/NFS – advisory Unknown
Break Oplock for PC-NFS Unknown
EMC Celerra appears to provide Mandatory Share Mode (open mode) locking for concurrent
access with UNIX/NFS when the advisory locking protocol is adhered to. They make no
statement about PC-NFS. CIFS/9000 provides this locking feature at the HP-UX September
2001 Application Release.
EMC Celerra appears to provide byte range locking for UNIX/NFS when the advisory locking
protocol is adhered to. They make no statement about PC-NFS. CIFS/9000 provides byte
range locking for UNIX, UNIX/NFS and PC-NFS.
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Anecdotal evidence suggests Celerra has this feature. See Appendix B.5