Francisco Jose Montilla wrote:
> Greetings to everybody...
>
> I've been setting up linux RAID (mainly 0, 1 or 5) for a while,
> always on servers with UWSCSI discs, kernel 2.0.36, and I'm willing to
> discuss performance issues, interchange opinions and such.
...
> I'm setting up a 0+1 RAID, with a 2.2.5 kernel, raidtools
> 19990309-0.90, kernel raid patch raid0145-19990309 (compiled as SMP).
I have problems with same raidtools under 2.0.36-SMP (compilation
fault); posted this a few days ago to the list - do you have any idea.
> md0 (O) has hda,hdb and md1 has hdc,hdd. What do you think? It
> will be better to do them with hda,hdc/hdb,hdd? md2 is the 0+1 RAID.
Maybe performance will increase a little bit if you stripe over the two ide
controllers (hda / hdc), but I think CPU-load will increase also. Maybe you
are decreasing the performance of the UW-disks by using disks at the ide
controllers at the same time (because the ide controllers need support of the
CPU).
> I noticed while benching that the first IDE port (md0) behaves
> substantially better (about a 15%) than the second, I assume this is
> normal, as happened with crappy 486/586 Motherboards, although I didn't
> expect that in this (a while ago) expensive mobo...
I don't have so much experiences in using ide ports (concerning benchmarking)
because I always use SCSI. A higher performance on the first port of each
controller is quiet normal (I think), because commands are reaching the
master device first and will then be given to the slave (if they belong to
it).
> I'm very excited with the new RAID version (I have always used
> raidtools 0.50 ans stock 2.0.36 kernel) it gives the feeling things have
> evolved a lot in advance!
I think the 0.90 raidtools are much more stable than the (I used once) 0.36
tools. If performance is better? I don't know, because I did not use 0.90
tools and 0.36 tools on two machines which are completely identical.
Regards, Dietmar
