Managing NFS and KRPC Kernel Configurations in HP-UX 11i v3 (762807-001, March 2014)

2.4.2 rpc_svc_cotsmaxdupreqs
Description
The rpc_svc_cotsmaxdupreqs tunable controls the size of the duplicate request cache that detects RPC
level transmissions on connection-oriented transports such as TCP. This cache avoids processing
retransmitted requests that are non-idempotent.
Tested Values
Default: 1024
Min: 1
Max: 2048
Note: If the tunable is set to a value greater than 2048, an
informational warning is issued at runtime. Any value
greater than 2048 is beyond the tested limit.
Restrictions on Changing
The rpc_svc_cotsmaxdupreqs tunable is dynamic. System reboot is not required to activate changes
made to this tunable. However, if the cache is full, decreasing the current value has no effect until the
system is rebooted.
Modifying the Value
Increasing the value of this tunable higher than the default can result in longer search times to find
entries in the cache. This can affect the performance of the NFS server. If a non-idempotent request is
mistakenly serviced twice by the NFS server, decreasing the value of this tunable can trigger false
failures on the NFS client side. For example, if an attempt to create a directory returns a status of
failed but the directory is actually created, the retransmitted MKDIR request was not detected by the
server.
2.4.3 rpc_svc_default_max_same_xprt
Description
The rpc_svc_default_max_same_xprt tunable controls the maximum number of requests that are
processed for each transport endpoint, (or connection), before switching transport endpoints. The
KRPC has a pool of service threads and a pool of transport endpoints. Any of the service threads can
service requests from any of the endpoints. To enhance performance, multiple requests are serviced
on each transport endpoint before switching endpoints.
Tested Values
Default: 8 requests
Min: 1 request
Max: 64 requests