HP-UX Reference (11i v2 04/09) - 5 Miscellaneous Topics (vol 9)

bufpages(5) bufpages(5)

(Tunable Kernel Parameters)

NAME

bufpages, nbuf, bufcache_max_pct - TO BE OBSOLETED

DESCRIPTION

These tunables, traditionally used for sizing a static buffer cache, are deprecated. The recommended way

to conﬁgure a static buffer cache is to set the tunables

dbc_min_pct and dbc_max_pct to the same

value. Please refer to

dbc_min_pct(5)

and dbc_max_pct(5)

, or consult HP support for more infor-

mation.

Note that

bufpages and nbuf were speciﬁed in units of 4K physical pages, and

dbc_min_pct and

dbc_max_pct are speciﬁed in units of percentage of physical memory.

EXAMPLES

If you have a system with 1GB memory (1048676 KB), and you used to tune your buffer cache with buf-

pages=8000 (8000 4K pages), you can determine what is the equivalent percentage of physical memory

that your buffer cache is using:

((8000 * 4)* 100) / 1048576

This is roughly 3% of physical memory. Therefore you can tune your system to use a static buffer cache of

the equivalent size by setting both dbc_min_pct and

dbc_max_pct to 3:

# kctune dbc_min_pct=3 dbc_max_pct=3

WARNINGS

All HP-UX kernel tunable parameters are release speciﬁc. These parameters (bufpages, nbuf, and

bufcache_max_pct

) will be removed in a future release of HP-UX.

Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-

ter values. After installation, some tunable parameters may no longer be at the default or recommended

values. For information about the effects of installation on tunable values, consult the documentation for

the kernel software being installed. For information about optional kernel software that was factory

installed on your system, see HP-UX Release Notes at

http://docs.hp.com

AUTHOR

bufpages, nbuf, and bufcache_max_pct

were developed by HP.