nproc values

[Betty Fessler]

On an HP-UX.B.10.20 nproc maxvalue is memory limited. How do I calculate what my limit is if I have say 2GB? Is this based on bytes?

[Bill Hassell · Accepted solution]

The wording is a bit misleading. You don't calculate nproc based on RAM, it is based on what your server needs. What the messages says is that if you increase nproc to 50,000 nfile would also have to be increased to perhaps 300,000 or so) then the kernel will be too big to boot up. 10.20 has been obsolete for several years and does not have the ability to run a kernel larger than about 12-15megs.

nproc is the size of the process table, and you can see the current number of processes with either sar -v 1 or ps -e|wc -l. Now if nproc is currently 500 and you have run out of process table entries (console/syslog says: "proc: table is full") then increase it to 1500 or 2000, then monitor the value.

[morganelan]

nproc's allowed values is 100 - 30000

This may be set higher, but more will not be used. Setting nproc below 110 will interfere with the systems ability to execute in multi-user mode. Some configurations may have a higher minimum.

nproc must be greater than nkthread + 100.

nproc must be greater than maxuprc + 5.

Recommended values:1000 processes per processor.

The value should be lowered only to limit the number of processes on the system, or when there is memory pressure and the value of nproc is far above the expected usage.

nkthread must be strictly greater than nproc. Default equations ensure this, as well as runtime kernel checks.

nfile and ninode should be increased (and are not by default) to allow applications to manipulate files.

ksi_alloc_max should be increased, as the default formula is multiple of nproc.

maxuprc must be less than nproc.

Some of these other tunables used to adjust automatically with changes in nproc. These adjustments must now be made explicitly.

Other tunables may require a reboot to take effect. So, dramatic increases in nproc without reboot should be made with caution.

[Ranjith_5]

Hi Betty,

nproc value is heavily dependent on your expected workload, but for most systems, 1024 is enough for the maximum number of processes. If you know better, set it higher. Don't blindly overconfigure this by setting it to 30000 when you'll have only 400 processes in your workload, as nproc influences various formulas in sam, and also has secondary effects, like increasing the size of the midaemon's shared memory segment (used by Glance to keep track of process data). Process table utilization is tracked in Glanceâ s System Tables Report: check the utilization periodically and plan to bump up nproc when you see its gets over 80 percent utilization during normal processing.

Regards,
Syam

[Betty Fessler]

Thanks for the replies nproc value doubled
w/o problem.