topic Re: Upgrade to RHEL4 - Worse performance? in Operating System - Linux

Upgrade to RHEL4 - Worse performance?

DJMS — Wed, 15 Nov 2006 19:10:53 GMT

We recently upgraded from RH9 to RHAS4 (update 2) on a DL380 G4. The latest PSP7.60 and firmware updates have been applied. We're seeing a 30% negative performance hit after the upgrade. Anyone else see this?

An example... A database is continuously rebuilt on the server. Previous to the upgrade, it averaged 8300 seconds from start to finish. Now, we're lucky to break 10,000 seconds. No hardware or filesystems were modified, just the upgrade on the root partition.

Re: Upgrade to RHEL4 - Worse performance?

Patrick Terlisten — Thu, 16 Nov 2006 01:06:49 GMT

Hello DJMS,

please give us more informations about your enviroment:

- how much CPUs, RAM is in you server?
- which database do you use?
- used RAID level? Hardware- or Software-RAID? How many disks?
- Is RHEL4 supportet with you database?

Regards,
Patrick

Re: Upgrade to RHEL4 - Worse performance?

Steven E. Protter — Thu, 16 Nov 2006 01:52:54 GMT

Shalom,

The OS uses more memory so an impact on performance is likely. Also, any kernel or parameter tuning you did is gone. That work needs to be done over.

This could also be a problem with HP's drivers or the lack of them after the upgradee.

SEP

Re: Upgrade to RHEL4 - Worse performance?

DJMS — Thu, 16 Nov 2006 05:15:15 GMT

Standard DL380 G4 with dual 3.60Ghz Xeons, 4GB RAM, six 10K RPM SCSI drives (maybe 15k, though I believe 10k). Drives are split off into 3 RAID0+1 groups, default 128kb stripes, hardware raid off the interal 6i. Database is Informix C-ISAM.

No tuning or kernel performance tweaks were in place before.

It was literally just an upgrade of the OS and the PSP (the drivers are there), everything else stayed the same.

Re: Upgrade to RHEL4 - Worse performance?

dirk dierickx — Fri, 17 Nov 2006 02:49:42 GMT

2.6 used by rh4 is a bit more advanced and has some tricks. there are some kernel tuning params that can be changed, like vm.swappiness (use sysctl). also 2.6 contains a bunch of different schedulers check this link on RH site for more info: http://www.redhat.com/magazine/008jun05/features/schedulers/

it could also be that some other (new) process is taking up a lot of precious CPU time, check with 'top' if there are some strange processes running.

lastly, if you're using X (with gnome/kde) you'll get a serious performance impact as well.