NFS server grace period
The NFS version 4 (NFSv4) protocol provides functionality that lets system administrators enable a grace period on the NFSv4 server for special handling of specific operations.
Within this grace period, administrators can manage locking, read operations,
and write operations for the entire duration of the server lease. Locks and
their associated states can be recovered by clients through reclaim-type locking
requests.
Note: Not all states reclaimed by clients in the grace period can
be guaranteed to be the state held by the server in the previous instance.
The state that is reclaimed during the grace period is guaranteed to be the
correct one as defined by the NFSv4 RFC.
Beginning with AIX 5L Version 5.3 with the 5300-05 Technology Level, administrators can use the grace period on NFSv4 servers. The grace period is disabled by default. To enable the grace period on the server, use the SMIT menu or the chnfs command line interface.
When the grace period is enabled, the NFSv4 server records state information to disk in the /var file. The recorded state is reclaimed automatically when the server restarts.