Date: Fri, 30 Oct 1998 10:53:19 -0600 (CST) From: Mike Nguyen <mikenguyen@sprintmail.com> To: Tom <tom@uniserve.com> Cc: "stable@freebsd.org" <stable@FreeBSD.ORG>, Milliken@hschpt06.hou.ucarb.com, Scott <MillikS@salestech.com> Subject: RE: RAID support in FBSD? Message-ID: <XFMail.981030105319.mikenguyen@sprintmail.com> In-Reply-To: <Pine.BSF.4.02A.9810300821050.6748-100000@shell.uniserve.ca>
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On 30-Oct-98 Tom uttered:
>
> On Fri, 30 Oct 1998, Milliken, Scott wrote:
>
>> > in degraded mode, you want SCSI-SCSI box, something from
> ...
>> If you really want the fastest performance then you
>> might want to consider a system that moves RAID completely offline from
> ...
>
> Thats exactly what a SCSI-SCSI box is, and exactly what is being talked
> about. No need for your long description.
>
> Besides, a host based RAID controler takes RAID processor "offline" too.
> A DPT PM334 has a dedicated CPU and RAM, it just happens to be on a PCI
> card.
A SCSI-SCSI RAID unit that I have had good experiences with are HP AutoRAIDs
(whoa, something from HP that isn't overpriced and doesn't suck, though still
not exactly cheap). The AutoRAID 12H has 4 SCSIs internally, and 12 disk slots,
which with 18.2GB drives can give you 155 GB or so, though of course you can use
9.1GB and 4.3GB drives (one downside: you have to buy drives from HP, they come
in a special enclosure). Also, two host SCSI channels, two controller cards w/
up to 128MB cache each; we use the dual paths on our HP 9000s for high
availability.
The neat thing about these, and this is what makes me recommend them, is that
if you don't allocate all the disk space, it will use that unallocated space to
keep more frequently used data in RAID 0+1. It's sorta like a HSM setup, where
you have the cache for the most recent stuff, down to the RAID 0+1 cache, and
then everything is in RAID5. With 9.1GB drives, we have 78GB or so of usable
space (after the hot spare and RAID 5 overhead), and we just allocate 70GB, and
leave the rest to the RAID 0+1 space.
Very fast (though not as fast as EMC, but hey, it's load cheaper), easy to set
up (front panel or software w/ HP-UX or LoseNT). I give it a thumbs up.
Mike.
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Mike Nguyen <mikenguyen@sprintmail.com> - UNIX Sysadmin and Geek
Pager (800) SKY-8888 pin# 1138368
or 1138368@skytel.com
"His super power is to turn into a scotch terrier."
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