HP-UX 11i Version 2 Release Notes (October 2003)

General System Administration

File Systems Tunable Parameters

Chapter 4

File Systems Tunable Parameters

Many of the HP-UX File Systems tunable parameters are now dynamic tunables (their

value can be modified without the need to reboot the system). Several default values and

allowed values for File Systems tunables have also been modified for performance,

usability, and/or system availability reasons.

Summary of Change

HP-UX File Systems now has 13 dynamic tunable parameters available in HP-UX 11i

v2. Their values can be modified dynamically using the tunables infrastructure

interfaces (e.g., kctune (1M), kcweb (1M)

, settune (2)).

The following File Systems tunables were static in previous HP-UX releases, and have

been converted to dynamic tunables in HP-UX 11i v2. In addition to making these

tunables dynamic, some of the default and/or allowed values have been modified. See the

manpages for details:

• nfile (5)

• nflocks (5)

• dbc_min_pct (5)

• dbc_max_pct (5)

• aio_max_ops (5)

• aio_listio_max (5)

• aio_prio_delta_max (5)

The following are new File Systems dynamic tunables:

• fs_symlinks (5) - Maximum number of symbolic links used to resolve a path name

• aio_proc_threads (5) - Maximum number of process threads allowed in AIO pool

• aio_monitor_run_sec (5) - Frequency of AIO thread pool monitor execution (in

seconds)

• aio_proc_thread_pct (5) - Percentage of all process threads allowed in AIO pool

• aio_req_per_thread (5) - Desirable ratio between number of pending AIO requests

and servicing threads

The maxfiles_lim (5) tunable has been dynamic in previous HP-UX releases, but its

default and allowed values have been modified. See manpage for details.

The following file systems tunables remain static (system reboot is required when

modified), but have been enhanced with new default and/or allowed values. See

manpages for details:

• maxfiles (5)

• ncsize (5)

• dnlc_hash_locks (5)

1. For more information about kcweb, see “HP-UX Kernel Configuration” on page 83.