NFS file-attribute cache tuning

NFS maintains a cache on each client system of the attributes of recently accessed directories and files.

You can set several parameters with the mount command to control how long a given entry is kept in the cache. They are as follows:

actimeo

Absolute time for which file and directory entries are kept in the file-attribute cache after an update. If specified, this value overrides the following *min and *max values, effectively setting them all to the actimeo value.

acregmin

Minimum time after an update that file entries will be retained. The default is 3 seconds.

acregmax

Maximum time after an update that file entries will be retained. The default is 60 seconds.

acdirmin

Minimum time after an update that directory entries will be retained. The default is 30 seconds.

acdirmax

Maximum time after an update that directory entries will be retained. The default is 60 seconds.

Each time the file or directory is updated, its removal is postponed for at least acregmin or acdirmin seconds. If this is the second or subsequent update, the entry is kept at least as long as the interval between the last two updates, but not more than acregmax or acdirmax seconds.