nfs:nfs_lookup_neg_cache

Description

Controls whether a negative name cache is used for NFS version 2 mounted file systems. This negative name cache records file names that were looked up, but not found. The cache is used to avoid over-the-network look-up requests made for file names that are already known to not exist.

Data Type

Integer (32-bit)

Default

1 (enabled)

Range

0 (disabled) or 1 (enabled)

Units

Boolean values

Dynamic?

Yes

Validation

None

When to Change

For the cache to perform correctly, negative entries must be strictly verified before they are used. This consistency mechanism is relaxed slightly for read-only mounted file systems. It is assumed that the file system on the server is not changing or is changing very slowly, and that it is okay for such changes to propagate slowly to the client. The consistency mechanism becomes the normal attribute cache mechanism in this case.

If file systems are mounted read-only on the client, but are expected to change on the server and these changes need to be seen immediately by the client, use this parameter to disable the negative cache.

If you disable the nfs:nfs_disable_rddir_cache parameter, you should probably also disable this parameter. For more information, see nfs:nfs_disable_rddir_cache.

Commitment Level

Unstable