HP-UX 11i v2 Installation and Update Guide, December 2005

Controlling Memory Utilization of VxFS 3.5 on HP-UX 11i v2
Controlling the inode Cache
Appendix C 165
Controlling the inode Cache
As a matter of course, VxFS file systems allocate and free up inodes as
required by the load on the file system. VxFS caches these inodes for
better performance (faster lookups). In general, larger inode caches help
file systems perform better for file server and web server loads. The
global (static) tunable vx_ninode represents the maximum possible size
of the VxFS inode cache.
Normally, the size of the inode cache is decided (auto-tuned) at boot time
by VxFS depending on the amount of physical memory in the machine,
provided that the value of vx_ninode is set to zero (default).
However, systems low on RAM (typically less than or equal to 1 GB/CPU)
may not require a large inode cache if file systems are not exposed to file
server and web server loads, or when file system performance is not
critical. HP recommends that you set the value of vx_ninode to more
than that of nfile, an HP-UX tunable that represents the maximum
number of file descriptors.