Common Misconfigured HP-UX Resources (April 2006)

The dependency on the ninode tunable is reduced with the introduction of the following two
tunables:
• ncsize — Introduced with PHKL_18335 on HP-UX 10.x. Determines the size of the Directory
Name Lookup Cache independent of ninode.
• vx_ncsize — Introduced in HP-UX 11.0. Used with ncsize to determine the overall size of the
DNLC.
On HP-UX 11i v1 and earlier, while you can tune ncsize independently of ninode the default value
is still dependent on ninode, which is calculated as follows:
(NINODE+VX_NCSIZE)+(8*DNLC_HASH_LOCKS)
On HP-UX 11i v2 and later, the default value for ncsize is 8976.
Beginning with JFS 3.5 on HP-UX 11i v1, the DNLC entries for JFS files are maintained in a separate
JFS DNLC, which is sized by vx_ninode; therefore, vx_ncsize can be set to 0. On HP-UX 11i v2,
the vx_ncsize parameter has been removed.
Configuring Your HFS Inode Cache
On HP-UX 11i v1 and earlier, the default size of the HFS inode cache is based on a number of
tunables, most notably nproc, which is calculated as follows:
((NPROC+16+MAXUSERS)+32+(2*NPTY)
On HP-UX 11i v2 and later, the default size of ninode is 4880.
However, some systems will need to configure a larger HFS inode cache, and some systems will need
to configure a smaller cache. The first thing you need to remember is how many HFS file systems you
presently have. If the boot file system (/stand) is your only HFS file system, then you can configure
ninode with a very low size (maybe 200-400). If you configure a small HFS inode cache, be sure
that the DNLC is configured appropriately for other file system types (such as NFS) by configuring the
ncsize tunable.
At a minimum, you need to configure the HFS inode cache so that it is large enough to hold all of the
HFS files that are open at any given instance in time. For example, you may have 200,000 HFS
inodes, but only 1000 are simultaneously opened at the same time. If so, give your system some
headroom and configure ninode to be 4000.
If you use mostly HFS files systems, the default value of ninode is still good for many systems.
However, if the system is used as a file server, with random files opened repeatedly (for example as a
Web server, mail server, or NFS server), then you may consider configuring a larger ninode value
(perhaps 40,000-80,000). When configuring a large ninode cache, remember the memory
resources that will need to be allocated.
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