[CentOS-virt] SATA vs RAID5 vs VMware
Luke S Crawford
lsc at prgmr.com
Fri Sep 25 02:46:53 UTC 2009
Philip Gwyn <liste at artware.qc.ca> writes:
> I have strange behaviour on a server that I can't get a handle on. I have a
> reasonably powerful server running VMware server 1.0.4-56528. It has a RAID5
> build with mdadm on 5 SATA drives. Masses of ram and 2 XEON CPUs. But it
> The problem seems like a disk problem. I grow to suspect that SATA isn't ready
> for the big time. I also grow to dislike RAID5.
Personally, I will use RAID5, and I will use SATA, but I will not use
SATA with RAID5 except in 'tape replacement' roles. The weak bits of
RAID5 (read/ write cycle on sub-stripe writes) are often exasterbated
by the weak bits of SATA (slow seek time, slow rotational speed)
creating a perfect storm of suck.
Not to say that's your primary problem.
Actually, it sounds a whole lot like the problems I get with xen on
heavily used servers, if I don't assign a core exclusively to the dom0
(or at least give it a very high priority.) But I have little knowledge
of or experience with VMware, so I don't know if you have a
Luke S. Crawford
http://prgmr.com/xen/ - Hosting for the technically adept
http://nostarch.com/xen.htm - We don't assume you are stupid.
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