> Here my results with 6 * IBM DNES 9GB U2W (4K blocksize):
>
> -------Sequential Output-------- ---Sequential Input-- --Random--
> -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> 5 768 6582 97.6 38862 61.6 17510 51.0 7497 96.3 41476 30.5 346.0 5.5
> 6 768 6575 97.4 39471 60.1 15493 44.2 7577 97.3 40808 33.3 371.9 6.3
> 7 768 6625 97.6 40965 59.9 14219 40.3 7592 97.7 42571 35.9 271.1 4.9
> 8 768 7121 99.8 72177 73.5 21740 49.5 7711 97.9 64926 45.6 265.8 3.8
>
> 5) Software Raid 5 on one Adaptec U2W (chunksize=64 stride=16) 2.2.14
> 6) Software Raid 5 on one Adaptec U2W (chunksize=32 stride=8) 2.2.14
> 7) Software Raid 5 on one Adaptec U2W (chunksize=8 stride=2) 2.2.14
> 8) Software Raid 0 on one Adaptec U2W (chunksize=4) 2.2.14
Looks quite better than mine (but you have more disks).
And 4 : 6 disks is not much different than 25 : 40 MB/s.
But it should be more with this type of disk, shouldn't it ?
And it also doesn't explain why it did not get more when using faster disks.
> Have you used the stride option when creating the filesystem and what
> blocksize are you using?
Of course 8) I use to read manuals before ;-)
> > I?m still trying to get why this is like that. Looking at the 2 UW channels
> > with 2 * 40MB/s and at a single drive rate of about 15-18MB/s, there should be
> > more throughput possible.
> >
> What board are you using and is the controller onboard?
It's a Gigabyte GA6BXDS and the AIC7895 IS onboard.
> Read the excellent howto from Jakob OEstergaard!
> http://ostenfeld.dk/~jakob/Software-RAID.HOWTO/Software-RAID.HOWTO.txt
Already did some time before.
Thomas
