topic Re: sysdef versus kctune in Operating System - HP-UX

sysdef versus kctune

NDO — Wed, 18 May 2016 07:41:52 GMT

Hi All!

I come across a situation where by I was told by the application vendor that I need to change the value of maxdsiz_64bit to the value of 1048576, but when I run the following command:

kctune | grep maxd
maxdsiz                      2147483648  2147483648  Immed
maxdsiz_64bit                2147483648  2147483648  Immed

but when I use other command, I see something different:

sysdef | grep maxdsiz_64bit
maxdsiz_64bit            524288          -        256-1048576    Pages   -

So now I am confused , what is the real value of maxdsiz_64bit!!

I am running hp-ux 11.31 v3 on ia64 hp server BL860c server.

Please can someone help?

Re: sysdef versus kctune

Patrick Wallek — Wed, 18 May 2016 13:07:23 GMT

Both values are correct.

The output of kctune is shown in BYTES, so the value is 2,147,483,648 bytes / 2,087,152 KB / 2,048 MB / 2 GB.

The output from sysdef is shown in the number of memory pages (notice the word PAGES at the far right of the output), where a page is 4096 bytes. So 524,288 pages times 4,096 bytes per page = 2,147,483,648 bytes or 2 GB.

Re: sysdef versus kctune

NDO — Wed, 18 May 2016 13:22:42 GMT

Ok, thanks a lot, now to set it to 1048576 pages what sysntax shoud I use? Please

Re: sysdef versus kctune

Patrick Wallek — Wed, 18 May 2016 16:38:23 GMT

1,048,576 pages = 4,294,967,296 byes (4 GB).

To set that value, use kctune.

# kctune maxdsiz_64bit=4294967296

Answer yes to the question about updating the automatic backup configuration.

Re: sysdef versus kctune

Bill Hassell — Wed, 18 May 2016 21:15:02 GMT

sysdef is deprecated for use in 11.31. Check the man page for sysdef at the bottom:

Note: sysdef will not be supported in future releases of HP-UX (refer
 to WARNINGS section below). So users are advised to use the
 kctune(1M) utility which provides additional information on kernel
 tunable parameters.
---
sysdef is provided for compatibility purposes only and is no longer
maintained since being marked for obsolescence in a future HP-UX
release.  The output from sysdef is known to be incorrect when
reporting values for some tunable parameters such as msgmap, sema, and
shmem.

The use of pages for kernel parameters has been quite confusing for many years.