Kernal Configuration

[ICT Infrastructure]

Hello,

We are currently migrating our Informix based application from HP-UX 10.20 to HP-UX11 (new server).

We are getting informix based errors whenever more than 1 person logs into the new server for testing (however no errors are appearing in syslog).

Prior to attempting to go live on the new server we made several kernal changes. We're now attempting to review the kernal as we thik think this may be at the root of the problems.

We think we may need to increase maxusers but we're not sure exactly what effect this will have.

Any advice of kernal tuning would be appreciated.

Thankyou.

[Stefan Farrelly]

This isnt much to go on. Increasing maxusers is not a problem - it wont cause any adverse effects so go ahead and try it, but by default it should let > 1 user log on!

[Robert-Jan Goossens]

Hi,

Informix uses maxusers=128 or higher, we use 200.

Hope ir helps,

Robert-Jan.

[ICT Infrastructure]

Thanks. Our maxusers is currently set to 400. We do not have any problems with users logging in but I think the maxusers parameter is affecting other values such as the formaula used to calculate nfiles. We need to increase maxusers to at least 1000 in order to get the high value required for nfiles. However we will only ever have 200 users on this application (max).

[kish_1]

my informix server has maxusers are 512 and go ahead and increase

[Pete Randall]

We're an Informix shop running on HP-UX 11.0. Our tunable kernel paramters are set as follows (from /stand/system):

STRMSGSZ 65535
max_thread_proc 256
maxdsiz 0X3B031000
maxswapchunks 9707
maxuprc 2048
maxusers 200
ncallout 3220
nfile 114548
nkthread 2048
nproc (20+16*MAXUSERS)
npty 500
nstrpty 60
num_tachyon_adapters 5
semmni 4096
semmns 4096
semmnu 1024
semume 1024
shmmax 4294967296
shmmni 512
shmseg 256



Not all, but most of these paramters are tuned explicitly for Informix with approximately 100 online users. Maybe you can spot something from this.

Pete

[Bill Hassell]

maxusers is simply a crutch to use instead of setting kernel values directly. I would leave maxusers at 100-200, then erase the formula for nfile and nproc, and set these values directly. The formulae do not scale correctly for database and several other applications. If you need 25000 for nfile, then set it to that value. Use sar -v 1 to see how many files are opened at the same time. Also, change ninode to a fixed value, perhaps 500. It will go out of control if you leave it as a formula. Set nproc similarly to nfile--use sar -v 1.