Dell PowerStore Configuring Multiprotocol File Sharing

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File system locking policies

SMB and NFS have their own locking semantics. Protocol specifications define lock ranges as mandatory for SMB but may be advisory for NFS. NFSv3 uses a separate protocol (NLM) that is always advisory. NFSv4 has a lock management that is integrated in the protocol itself, but may also be advisory or mandatory, depending on the implementation.

A locking policy property is used to define the behavior. You can select one of the following locking policies for a multiprotocol file system:

Table 1. Locking policies for file systemsColumn one lists the locking policy, column two describes the meaning of each policy.
Setting	Description
Mandatory	This policy uses the SMB and NFSv4 protocols to manage range locks for a file that is in use by another user. If there is concurrent access to the same locked data, a mandatory locking policy prevents data corruption.
Advisory	(Default) In response to lock requests, this policy reports that there is a range lock conflict, but does not prevent access to the file. This policy allows NFSv3 applications that are not range-lock compliant to continue working, but risks data corruption if there are concurrent writes.