Vinum raid5 proformance problem

From: Torben Jakobsen (snuden_at_spanden.dk)
Date: 02/27/04 

Date: 27 Feb 2004 07:52:03 -0800

Hey....

Have some proformance issues with my vinum raid 5,
build with 5*120GB Maxtor ata133 harddrives and
its running on a Intel(R) Celeron(R) CPU 2.40GHz and
atapci0: Promise PDC20269 UDMA133 controller
atapci1: Promise PDC20268 UDMA100 controller

The raid5 itself outputs a very poor result, a basic ata100 disk
delivers a better result :O(
Have made some proformance tests with bonnie on every disk to see
if one of them or the controller is the problem, but it turns out
ok (see below).

drive d1 device /dev/ad4s1e
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
          200 20216 58.1 20451 25.7 17464 27.9 42096 98.0 215632 97.5 9506.2 97.8

drive d2 device /dev/ad6s1e
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
          200 17967 51.0 20432 24.9 17421 27.3 42760 98.0 228142 97.5 9672.3 95.7

drive d3 device /dev/ad8s1e
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
          200 29604 86.4 57013 77.1 34173 56.4 41743 97.9 205256 97.8 9202.2 97.6

drive d4 device /dev/ad10s1e
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
          200 29580 85.8 58001 75.8 34334 55.5 42729 98.4 200032 98.6 6445.1 79.5

drive d5 device /dev/ad11s1e
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
          200 19194 56.5 56132 72.7 27315 43.1 42955 98.5 222681 98.4 9520.8 98.5

The raid5 delivers a bonnie result like this.....

              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
          200 3506 12.6 3634 7.3 3476 6.1 41468 98.3 196285 97.3 9112.5 96.9

Here is my vinum config file.....
drive d1 device /dev/ad4s1e
drive d2 device /dev/ad6s1e
drive d3 device /dev/ad8s1e
drive d4 device /dev/ad10s1e
drive d5 device /dev/ad11s1e
volume raid
plex org raid5 512k
sd length 117239m drive d1
sd length 117239m drive d2
sd length 117239m drive d3
sd length 117239m drive d4
sd length 117239m drive d5

Any help with this problem will be very apreciated.