HP CIFS Client A.02.02 Administrator's Guide

Configuration File
Configuration Parameters
Chapter 7 111
nfsKernelCacheTime
NFS kernel is cached for this amount of time (in
seconds). A variable that can enable kernel caching by
NFS. This improves performance of certain types of
operations by reducing the number of calls sent over
the network. The deault setting is 0 second.
lookupStrategy As you probably know, the HP CIFS Client maps
between NFS requests and SMB/CIFS requests. On the
NFS side, files are referenced by unique identifiers,
called NFS file handles. On the HP CIFS side, files are
referenced simply by their path. The HP CIFS Client
must be able to determine the path given to an NFS file
handle. There are two strategies available to do this:
• pseudoInode
This strategy derives the NFS file handle as a hash
value from the path. The hash is chosen in a way
that makes efficient lookups possible, as long as the
depth of the file in the directory hierarchy is lower
than 27. The advantage of this strategy is the low
memory consumption: Files can be looked up on
demand, nothing has to be stored. The main
disadvantage is that NFS file handles change when
files are renamed. This leads to a conflict with Unix
semantics when open files are renamed: After
renaming, the handle of the open file is stale and
the file can not be accessed without reopening. It
also conflicts with a bug in the caching code of the
Solaris NFS client where the writeback occurs only
after closing the file, not during closing the file.
• database
In this strategy all NFS file handle to file path
relations are stored in an internal database. This is
the most secure and most compatible approach.
The disadvantage is that all this information must
be kept in memory. The HP CIFS Client needs
about 500kB more real memory and about 10MB
more virtual memory for each share that uses this
strategy.
The database strategy is the default.