This section describes NFS parameters for the rpcmod module.
Controls the number of TCP connections that the NFS client uses when communicating with each NFS server. The kernel RPC is constructed so that it can multiplex RPCs over a single connection. However, multiple connections can be used, if preferred.
Integer (32-bit)
1
1 to 231 - 1
Connections
Yes
None
In general, one connection is sufficient to achieve full network bandwidth. However, if TCP cannot utilize the bandwidth offered by the network in a single stream, then multiple connections might increase the throughput between the NFS client and the NFS server.
Increasing the number of connections doesn't come without consequences. Increasing the number of connections also increases kernel resource usage needed to keep track of each connection.
Unstable
Controls the duration of time on the NFS client that a connection between the NFS client and NFS server is allowed to remain idle before being closed.
Long integer (64-bit)
300,000 milliseconds (5 minutes)
0 to 263 - 1
Milliseconds
Yes
None
Use this parameter to change the time that idle connections are allowed to exist on the NFS client before being closed. You might want to close connections at a faster rate to avoid consuming system resources.
Unstable
Controls the duration of time on the NFS server that a connection between the NFS client and NFS server is allowed to remain idle before being closed.
Long integer (64-bit)
360,000 milliseconds (6 minutes)
0 to 263 - 1
Milliseconds
Yes
None
Use this parameter to change the time that idle connections are allowed to exist on the NFS server before being closed. You might want to close connections at a faster rate to avoid consuming system resources.
Unstable
Controls the size of the duplicate request cache that detects RPC- level retransmissions on connectionless transports. This cache is indexed by the client network address and the RPC procedure number, program number, version number, and transaction ID. This cache avoids processing retransmitted requests that might not be idempotent.
Integer (32-bit)
8192
1 to 231 - 1
Requests
The cache is dynamically sized, but the hash queues that provide fast access to the cache are statically sized. Making the cache very large might result in long search times to find entries in the cache.
Do not set the value of this parameter to 0. This value prevents the NFS server from handling non idempotent requests.
None
Examine the value of this parameter if false failures are encountered by NFS clients. For example, if an attempt to create a directory fails, but the directory is actually created, perhaps that retransmitted MKDIR request was not detected by the server.
The size of the cache should match the load on the server. The cache records non idempotent requests and so only needs to track a portion of the total requests. The cache does need to hold the information long enough to be able to detect a retransmission by the client. Typically, the client timeout for connectionless transports is relatively short, starting around 1 second and increasing to about 20 seconds.
Unstable
Controls the size of the duplicate request cache that detects RPC- level retransmissions on connection-oriented transports. This cache is indexed by the client network address and the RPC procedure number, program number, version number, and transaction ID. This cache avoids processing retransmitted requests that might not be idempotent.
Integer (32–bit)
8192
1 to 231 - 1
Requests
Yes
The cache is dynamically sized, but the hash queues that provide fast access to the cache are statically sized. Making the cache very large might result in long search times to find entries in the cache.
Do not set the value of this parameter to 0. It prevents the NFS server from handling non-idempotent requests.
Examine the value of this parameter if false failures are encountered by NFS clients. For example, if an attempt to create a directory fails, but the directory is actually created, it is possible that a retransmitted MKDIR request was not detected by the server.
The size of the cache should match the load on the server. The cache records non-idempotent requests and so only needs to track a portion of the total requests. It does need to hold the information long enough to be able to detect a retransmission on the part of the client. Typically, the client timeout for connection oriented transports is very long, about 1 minute. Thus, entries need to stay in the cache for fairly long times.
Unstable