[CentOS] Re: Centos 4.2 and Boot/Root on RAID?

Thu Oct 20 18:57:59 UTC 2005
Bryan J. Smith <thebs413 at earthlink.net>

Steve Bergman <steve at rueb.com> wrote:
> Good points as to the advantages of software RAID.
> This machine is fully certified by RedHat, but the
> CERC 6ch controller is uncertain,

The CERC 6ch uses the aaraid driver.
Administrative tools are largely lacking though.

It's also an old Intel i960-based design, so it's rather
sluggish.  At RAID-5 its so-so, the i960 is a bit of a
bottleneck with today's drives.  But at RAID-0, 1 or 10, the
i960 will be a massive bottleneck.

> so software RAID seems the right choice.

The question is, how are you going to do software RAID?  Are
you going to use the AIC-7xxx SCSI channels on the CERC 6ch?

If that does bypass the sluggish i960, then it would probably
be faster at RAID-5 and far, far faster at RAID-0, 1 or 10. 
But if you have to put the i960 in JBOD mode, the i960 still
might be a bottleneck to the SCSI channels.

Which means you're not going to see any better performance,
so you might want to just use the i960 hardware RAID.

[ SIDE NOTE:  This is why I don't like generalized RAID
discussions.  How to do RAID is a question of what hardware
you have -- for _both_ software or hardware. ]


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