3.10. NFS Read/Write Size Configuration Change

Prior to this UNICOS/mp release, the rsize and wsize parameters that can be specified when mounting an NFS file system could be silently changed (lowered) by the system. For example, if the administrator specified rsize=32768 and wsize=32768, and the NFS server was not on a directly connected network (that is, more than one hop away), the system would lower the values to rsize=16384 and wsize=16384 in an attempt to reduce the occurrence of NFS read/write timeouts.

The behavior did not allow UNICOS/mp to achieve the best possible NFS client performance in some cases. Consequently, the system was changed to maintain the values chosen by the administrator and the default values of 32768 if nothing was specified on the command line.

If a site experiences an increase in NFS read/write timeouts after installing this UNICOS/mp release, the administrator may want to consider explicitly lowering the rsize= and wsize= values.