3.7.0 HP StorageWorks HP Scalable NAS File Serving Software command reference guide HP Scalable NAS for Linux (AG513-96003, October 2009)

NOTE:

The NLM locking protocol is enabled by default on HP 4000 Scalable NAS systems.

It is disabled by default on the FS Option for Linux software-only product and on

HP X5500 Storage Gateway for Linux/HP Scalable NAS Clustered Gateway systems.

When the feature is enabled, the contents of the NFSD RPC reply cache are written

out to a file when a virtualized NFS server (vhost) is removed from the node. By

transferring the cache file to another node before the virtualized server is reactivated

there, the cache entries can be preloaded on the destination node, giving a more

transparent transition.

Without an RPC reply cache, clients that retry non-idempotent operations (operations

whose success invalidates their pre-conditions, such as create, remove, link, unlink,

rename, and so on) may see erroneous error returns. The conventional reply cache

prevents this problem. It is kept in memory on each node, with no provision to transfer

it between nodes or save and restore it. With the addition of virtualized NFS servers

that can move between nodes, clients are again exposed to spurious error returns.

The virtualized NFSD RPC reply cache feature allows the state of the NFSD RPC reply

cache to be associated with the relevant virtualized NFS server (vhost) and transferred

together with the virtualized NFS server.

To use this feature, you will need to create a directory for the reply cache. HP

recommends that the directory be placed in the administrative filesystem (for example,

_adminfs/protocols/nfs_1/reply_cache). The administrative filesystem

must be created manually and must be mounted on all nodes. (For more information

about the administrative filesystem, see mx config adminfs – administrative filesystem

commands, page 98 and also the HP Scalable NAS File Serving Software

administration guide.)

The options are:

-q or --query

Show the current status of the virtualized NFSD reply caches in the cluster (either

enabled or disabled). If the feature is enabled, the directory that will contain the