Informix and HP-UX 11.11 - relevant kernel patches

[Jason Dinsdale]

All,

Having performance problems with Informix 9.21 (32 bit) under HP-UX v11.11 on an RP3440 (dual core) using a VA7110 disk array.

My intuition tells me this is an application or database problem (not finger pointing here ... I'm the DBA also!), but I want to rule out the OS as the cause of the problems we're experiencing.

I'm wondering if there are any guidelines or recommendations on how to configure the OS for Informix, and whether there are any key patches that need to be installed? I know this used to be the case for Kernel I/O under 10.20 ... there might be something similar under 11.11?

TIA,

Jason Dinsdale

[Cheryl Griffin]

I searched the informix site and could only find documentation that listed patches for 10.20. Has 9.21 been certified for 11.11 by ibm? If so, I would expect to find patches listed in the system requirements section of their release notes or installation guide.

[Victor Fridyev]

Hi,
As far as I remember, the requirements regarding patches in Informix documentation usually mention very old stuff. If the latest QPK is installed, it's more than enough.
In any case you can see the required patches in the file called
$INFORMIXDIR/release/en_us/0333/ids_machine_notes_9.21.txt

HTH

[C Wood]

We are runnning HP-UX v11.11 but Informix 7.31.UD4 on RP5430. I had to load patch PHSS_30966. See if there is not a similar patch for ver 9.21

[Pete Randall]

Jason,

We recently moved to 11.11 as well, with Informix 7.31 FD1. I had to install nothing other than the latest quality packs and performance has been fine. Have you checked for other obvious performance issues, like swapping? Run "vmstat 1 10" and check the "po" column. If it's anything other than zero, you're in need of some more memory.


Pete

[Jason Dinsdale]

All,

Thanks very much for your contributions; we seem to have addressed some of our performance problems through a combination of kernel tuning and database tuning. In particular:

- max_thread_proc from 256 > 1024
- scsi_max_qdepth from 8 > 32

Since Informix is heavily multi-threaded, and we were leveling off at around 250 db sessions, this looked like a good candidate for tweaking. Also, I had configured the devices to a qdepth of 32, but not the kernel, which probably negated the scscictl settings I had implemented on the lvol device files.

As far as the database is concerned, the key change was tweaking the NETTYPE parameters so that CPU VPs are used for ipcshm connections, and NET VPs are used for TCP connections (we had the reverse).
The other change of note was the reduction of CPUVPS from 4 to 2; seems that CPUVPs 3 and 4 were not doing a great deal apart from contending for resources and making a general nusiance of themselves.

Since then the user population seems to have settled down, with a dramatic drop in cursing of the IT dept and/or database server. Sys admin nirvana?

Thanks,

Jason