topic Re: XP - performances. in Disk Enclosures

XP - performances.

TOMAS BERNABEU — Wed, 24 Jul 2002 09:14:25 GMT

xp512 with disc groups in raid 5.
4 FC of high performance.
8Gb memory cache.
lv's with striping of 4 discs and with block size of 256k.
dd with bs=256k gives 8Mb, the disc uses it to 12%.
5 dd bs=256k gives 80Mb/seg.
Oracle uses raw device with block size of 8k.
I need to improve much the performances.
I need that oracle writes many GB in just a short time.
ideas ?

Re: XP - performances.

Vincent Fleming — Wed, 24 Jul 2002 13:23:40 GMT

General rules:

1. make your LV block size 64k.
2. use LDEVs (luns) from as many array groups as possible (stripe across AGs)
3. use the same # of luns from each ACP pair. (stripe across ACPs)

Note that "dd" is not a good performance metric.

Good luck

Re: XP - performances.

Mark van Silfhout — Thu, 25 Jul 2002 05:44:02 GMT

Hi,

Instead of blockstriping try to use "extend-based" striping (with the default extentsize of 4 MB).

Regards,
Mark

Re: XP - performances.

Wilfried Unkauf — Fri, 26 Jul 2002 11:16:43 GMT

- you have to look for best performance of server (cpu and memory and io !) and xp512 and oracle !
- if you have a xp512 i think you have an hp support engineer for xp-config
- use few disks (over all channels) only for oracle redo-logs, strip all other tablespaces over all other disks
- make "correct" application-tests for extend-based-stripping and ??K-stripping (16,32,64,..) and check the performance (not only io) with sar, glance, perfview,..
- check oracle-performance (statspack) and optimize init.ora