Setting "ulimit" is Not Working and Throwing Errors

devUnix · 02-07-2012, 05:03 AM

Hi,

In order to increase "ulimit" I followed this article as it explains the same error that I receive while doing that on OpenSolaris (my local test box) as well as on Solaris 10 (production box):

http://blogs.oracle.com/hasham/entry...sing_number_of

Here is what I am running:

Code:

bash-3.2# ulimit -u
8021

Code:

bash-3.2# ulimit -u 25000
bash: ulimit: max user processes: cannot modify limit: Invalid argument

Code:

bash-3.2# ulimit -a
core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) unlimited
file size               (blocks, -f) unlimited
open files                      (-n) 256
pipe size            (512 bytes, -p) 10
stack size              (kbytes, -s) 8480
cpu time               (seconds, -t) unlimited
max user processes              (-u) 8021
virtual memory          (kbytes, -v) unlimited
bash-3.2#

Now setting "pidmax" as suggested in the article:

Code:

bash-3.2# set pidmax=60000
bash-3.2# echo pidmax/D | mdb -k
pidmax:
pidmax:         30000
bash-3.2#

It's not working.

Now setting "maxuprc" as stated in the article:

Code:

bash-3.2# set maxuprc=50000
bash-3.2# echo maxuprc/D | mdb -k
maxuprc:
maxuprc:        8021

It is also not working.

Some guesses:

Code:

bash-3.2# mdb
> maxuprc
mdb: failed to dereference symbol: unknown symbol name
> pidmax
mdb: failed to dereference symbol: unknown symbol name
>

Code:

bash-3.2# ulimit -u
8021
bash-3.2# ulimit -u 30000
bash: ulimit: max user processes: cannot modify limit: Invalid argument
bash-3.2#

Any help?

Side Note: At this point I am not concerned about the ulimit's ideal size or any philosophy behind it. I just need to do that on a production box per the instruction / requirement we have received. But as stated above, it is not working.

jlliagre · 02-07-2012, 10:37 AM

Quote:

Originally Posted by devUnix

Now setting "pidmax" as suggested in the article:

Code:

bash-3.2# set pidmax=60000
bash-3.2# echo pidmax/D | mdb -k
pidmax:
pidmax:         30000
bash-3.2#

It's not working.

That is because you are missing to set pidmax (and other tunables) properly. The article you cite tells to set them in the /etc/system file and then reboot for the kernel to get them, not to use the unrelated shell set command.

devUnix · 02-07-2012, 11:21 AM

Quote:

The article you cite tells to set them in the /etc/system file and then reboot for the kernel to get them, not to use the unrelated shell set command.

Not sure, then, why the "set" commands are shown in the article. However, changing "/etc/system" will make system wide changes- for all users. We want to do it for specific users. Besides, a reboot would be required. It's a production box which is not supposed to be rebooted without a change request/control.

jlliagre · 02-07-2012, 12:48 PM

Quote:

Originally Posted by devUnix

Not sure, then, why the "set" commands are shown in the article.

Because that's the correct syntax. Why do you think there is a problem with these "set" commands ?

Quote:

However, changing "/etc/system" will make system wide changes- for all users.

Indeed and the article is quite clear these settings are system wide. Three of them do not make sense "per user" anyway.

Quote:

We want to do it for specific users.

Then you might want to investigate resource controls, especially max-lwps.

Quote:

Besides, a reboot would be required. It's a production box which is not supposed to be rebooted without a change request/control.

If you need to raise tunable values than cannot be set dynamically, there is no other way outside rebooting. However, some of these variables looks like to be changeable online using kmdb, although it is always risky doing it on a production system.

By the the way, you missed to pass the correct option to mdb (mdb -k), that's the reason why your mdb commands failed.

devUnix · 02-08-2012, 12:59 AM

Quote:

Originally Posted by jlliagre

By the the way, you missed to pass the correct option to mdb (mdb -k), that's the reason why your mdb commands failed.

Could you please point out those incorrect commands the correct them as well?

jlliagre · 02-08-2012, 08:18 AM

You are missing to pass -k to mdb here:

Code:

bash-3.2# mdb
> maxuprc
mdb: failed to dereference symbol: unknown symbol name
> pidmax
mdb: failed to dereference symbol: unknown symbol name
>

devUnix · 02-13-2012, 12:26 PM

Quote:

Originally Posted by jlliagre

By the the way, you missed to pass the correct option to mdb (mdb -k), that's the reason why your mdb commands failed.

Nope. It is there in my OP:

"Now setting "pidmax" as suggested in the article: ..."

devUnix · 02-13-2012, 12:27 PM

Quote:

Originally Posted by jlliagre

You are missing to pass -k to mdb here:

Code:

bash-3.2# mdb
> maxuprc
mdb: failed to dereference symbol: unknown symbol name
> pidmax
mdb: failed to dereference symbol: unknown symbol name
>

I had tried with the "-k" option as well.

jlliagre · 02-13-2012, 01:04 PM

I do not question that but these error messages were caused by the missing "-k" option.

You need to tell at least once how you want the variables to be presented by appending a /D to the variable name, otherwise, nothing is displayed, eg:

Code:

# mdb -k
...
> maxuprc
> maxuprc/D
maxuprc:
maxuprc:      16165