Tuning the z/OS NFS client

This topic discusses performance tuning at the z/OS NFS client level. Performance of the z/OS NFS client is affected by the following installation parameters that can be tuned (see Table 1). The default value of each parameter is specified in parentheses.

Table 1. Client installation parameters for tuning
Parameter (value)
attrcaching (Y)
biod (6)
bufhigh (32)
datacaching (Y)
delaywrite (16)
dynamicsizeadj (Y)
readahead (8)

Most of the installation parameters that are specified in member BPXPRMxx in SYS1.PARMLIB can be overridden for a mount point by using the mount command. The exceptions to this are biod and bufhigh, which require restarting z/OS UNIX.

Table 2 shows mount parameters that affect performance and that can be tuned. The default values are specified in parentheses.

Table 2. Mount parameters for performance and tuning
Parameter (value)
attrcaching (Y)
datacaching (Y)
delaywrite (16)
readahead (8)
rsize (8192 for NFSV2) (For NFSV3 or NFSV4 - negotiated between the z/OS NFS client and the NFS server)
wsize (8192 for NFSV2) (For NFSV3 or NFSV4 - negotiated between the z/OS NFS client and the NFS server)
vers (4)