[CentOS] software raid

Thu Mar 29 17:02:19 UTC 2007
Feizhou <feizhou at graffiti.net>

chrism at imntv.com wrote:
> Feizhou wrote:
>> William Warren wrote:
>>> as soon as you goto software raid 5 you'll get a good performance 
>>> hit. Head for the hardware raid cards then.  You can get the 3ware 
>>> ide cards for 150 or less now.
>> don't know if it is still the case but ext3 + 3ware + ext3 = ultra 
>> slow. you'd want to use XFS or some other filesystem...

argh...i missed the raid5 on 3ware part.

> I keep hearing about this "slowness" thing.  Here is a bonnie++ run on 
> one of my spare machines.  This particular machine is also running 4 
> copies of Folding at Home in the background during the test.  The array 
> being tested is on a 3Ware 9550 card with 8 500gig barracudas.  The 
> filesystem is a standard ext3 filesystem with zero tweaks.  It doesn't 
> appear that slow to me, but perhaps I'm just easy to please.

<shrug> You are free to not believe or to believe. Maybe the latest 
Centos 4 kernel has a fix or something but ext3 + 3ware raid5 = slow 
while XFS would fly. Are your 8 500GB configured in raid5 or raid10? If 
it is raid10, then yes, it will fly. You switch to raid5 however and you 
will experience a slow down. This is not limited to 3ware boards lower 
than 95xx which suffer from lack of onboard memory to make things fly.