[Pc_Support] Re: Any recommendations on U160 SCSI RAID cards?

[Jason Boxman]

Bryan J. Smith <b.j.smith at ieee.org> said:
> From: Jason Boxman <jasonb at edseek.com>
>> I might be in the market for a Linux friendly SCSI RAID controller for a
>> RAID
>> 5 array of 4 Seagate Cheetah drives.  Anyone have any recommendations?
>
> New or used?

New.  It's for the office's dual P3 Coppermine setup.  It's a ServerWorks
III LE deal.  This one has a 64/66 and a 64/33 on different channels.  It's
a 2U case.

> If used, then there are plenty of Mylex eXtremeRAID 1100/2000 cards that
> are about 5 years old, but still very powerful StrongARM SA110 206MHz
> Ultra80/Ultra160 2-3 channel cards with 64MB SDRAM or so for maybe
> $100-250.  They will roast and toast anything i960-based.
>
> If new, then anything LSI MegaRAID SCSI "X" -- meaning 400MHz+
> Intel XScale (Superscalar StrongARM), like the SCSI 320-2X for PCI-X
> or maybe even the 320-2E for PCIe x8.  The latter can go in an SLI
> mainboard (one PCIe x8 channel for video, the other for the card),
> or any mainboard that has a good PCIe x4 or x8 slot if you're trying
> to avoid costs (although the board is $500, the commodity mainboard,
> CPU and DDR SDRAM will give you a good "bang for the buck").

Is there anything to be had that'll be happy with a box without PCI-X?  I
imagine those PCI-X cards are backwards compatible with a 64/66 slot?

>> Good RAID 5 performance is key.  If it has two ports, bonus, because
>> I'll run another 2 Cheetahs in RAID 1 for the OS partitions.
>
> Actually, when it comes to SCSI channels, you should typically span
> drives of the _same_ volume over _multiple_ channels.  I.e., 4 drives
> with 2 channels means you should have 2 drives on each channel,
> even (and especially) if they are in the same volume.

In this case, the cable situation is strained.  It's hard to get U160 cables
that'll fit in this case, since it's an upgrade of an existing rackmount
system with regular 68-pin drives and no hot swap bays or plans for any.  I
won't be able to split the RAID 5 into two cables of two and two drives each
due to space and difficulty-of-obtaining-cabling issues.  I would leap for
joy if I can recycle the existing, five head U160 cable we have so we can
run two of the six disks in hardware RAID 1, though.  (With a one port SCSI
RAID I'd need to do software RAID 1, which is fine with me, but I'd rather
just do it via hardware if the option exists.)

>> (The existing controller only has a single connector and is
>> quite old.  16MB of RAM for RAID 5 is painful.)
>
> Most everything is going to be 128MB+ these days.  Maybe older
> solutions might only be 64MB.
>
> But don't bother with anything i960/IOP30x-based.  At least go
> for a XScale/IOP33x, or possibly an older, used SA110-based.

Sounds good.