topic Re: rexec limitations? in Operating System - HP-UX

rexec limitations?

Michelle Weiss — Wed, 08 May 2002 21:00:21 GMT

I am experiencing a problem using the rexec command to log in to an HP N-class 11.0 system.
Error being received is 'no available ptys'.

As soon as we reach 176 npty's in use (according to gpm) it will not allow any other additional rexec logins. If someone gets out, then someone else is able to log in, but there seems to be a limitation to the number that are allowed (?) Telnet, remsh, and rlogins are fine, only a problem with rexec (which I must use because of prompts rec'd when users log in). We are using Hummingbird's Exceed, but I have verified that it is also a problem just running rexec from the command line, so I've ruled out a software problem.

My kernal params: npty, nstrpty, and nstrtel are all set to 400 and device files appear to be in order. Like I stated gpm states that only 176 pty's out of 400 available are in use.

Is there some other configuration setting somewhere that I need to increase to allow more rexec logins to this system??

Any help is appreciated!
Michell

Re: rexec limitations?

A. Clay Stephenson — Wed, 08 May 2002 21:05:14 GMT

I would do a sar -v and check for nfile overflows or possibly nproc overflows.

Re: rexec limitations?

Michelle Weiss — Wed, 08 May 2002 21:16:11 GMT

Am unable to run sar -v as I do not have a /var/adm/sa...

If it were nproc/nfile I believe I'd see processes failing (probably alot of them)?? Besides nproc on this system is set to 3461 and when I looked today I was running at around 2400. My nfile param is set at 53973.

I should clarify, we have always had this many users (around 250 concurrently) logging into this system, however over the past week we have been slowly converting them all over from Reflections (using telnet) to Exceed (using rexec), which is why we have just started seeing this problem.

Thank you for the suggestion - any other thoughts out there??

Re: rexec limitations?

Trevor Dyson — Wed, 08 May 2002 21:55:45 GMT

Do you have enough pty device files.

look under /dev/pts. The files that do not begin with a 't' are used by rlogin and rexec.

to create 400 then use:

insf -e -d pts -n 400

Re: rexec limitations?

Trevor Dyson — Wed, 08 May 2002 22:47:00 GMT

Correction:

insf -e -d pts -s 400

Re: rexec limitations?

S.K. Chan — Wed, 08 May 2002 22:47:17 GMT

I would increase the pty's. Take a look at what do you currently have..

# ls -l /dev/pty |wc -l
# ls -l /dev/ptym | wc -l
==> If you got 61 then it's the default and you need to bump it up.

First in SAM, increase "npty". Depending on how many connection you need. I would say 512 to start off. After the system reboots with the new kernel, build the device files.

# insf -d ptys -n 512
# insf -d ptym -n 512

Re: rexec limitations?

Michelle Weiss — Thu, 09 May 2002 13:08:20 GMT

Thanks for the replies!

Trevor - I tried your suggestion and recreated device files, however I still have the problem.

After that, I also tried a suggestion from HP to run a straight 'insf -e', this did not work either...

S.K. - I ran your cmds as well and found that I have 401 in /dev/pty and 801 in /dev/pts. Should be plenty (?)

Help????