[SUMMARY] Kernel Parametres in Sol 2.6, 2.7

From: Paramasivam, Meenakshisundaram (mparamas@iupui.edu)
Date: Mon Apr 26 1999 - 14:21:03 CDT


In response to unrelated circumstances, I had to cold-install 2.7 on the
system that had the problem (under 2.6). I have included all the responses
so that they may be useful for those having the same problems like I had. I
did not do any tests on 2.7 yet.

Sundar Paramasivan mparamas@iupui.edu
Systems Administrator
Indiana University Radiology/Imaging Science

From: Burch Seymour RTPS [bseymour@ns.encore.com]

First run sysdef and see what your actual limits are. For example I
see this from a plain install with all defaults on my Sun 450 server
running Solaris 7:

* Process Resource Limit Tunables (Current:Maximum)
  Infinity:Infinity cpu time
  Infinity:Infinity file size
  Infinity:Infinity heap size
0x00800000:Infinity stack size
  Infinity:Infinity core file size
0x00000040:0x00000400 file descriptors
  Infinity:Infinity mapped memory

* IPC Shared Memory
  16777216 max shared memory segment size (SHMMAX)
     1 min shared memory segment size (SHMMIN)
   100 shared memory identifiers (SHMMNI)
    16 max attached shm segments per process (SHMSEG)

I changed the SHMMAX by adding a line to /etc/system, though it's
not as straightforward as you might imagine...
Here's my lines from /etc/system

set shmsys:shminfo_shmmax=16777216
set shmsys:shminfo_shmseg=16

Hope this helps.
From: David Evans [DJEVANS@au.oracle.com]

Try http://docs.sun.com and look at the on-line Answerbooks. There is
a kernel parameter section in one of them.
From: Umakant Wadiyar [wadiyu@sweng.stortek.com]

To change the kernel parameters , You need to set the parameters in
/etc/system file and reboot the system .
From: Harry Levinson [levinson@ll.mit.edu]

I have not encountered a situation where a properly written program (ie. no
memory leaks) could be helped by adjusting the parameters you list. This
is because Solaris, unlike HP-UX, gives each process the maximum reasonable
virtual memory space it needs. Have you tried 'vmstat 5'? Pay pariticular
attention to the 'po' column. If this is non-zero than you are short of
memory and the application is being paged out. How about 'iostat 5'? Do
you have a lot of IO activity or a high wt or sy number? Finally, how much
network access does the app generate? Are you sure you are CPU bound?

What sort of application is this? Is this a commercial product or a custom

-----Original Message-----

Even though I have 512MB RAM installed with sufficient disk swap space (2.5
times RAM size) on Ultra-1, Sol2.6 machine, the application runs too slow
and takes up a lot of cpu time.

Are there any kernel parameters that I could change?

How to change kernel parameters in 2.6 and 2.7 (Solaris 7) so that I get to
increase the following;

maximum data size
maximum stack size
maximum shared segment size

Is there a procedure described somewhere? Any pointers is welcome.

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