classiccmp server hardware

From: Doc Shipley <doc_at_mdrconsult.com>
Date: Sun Oct 10 12:47:25 2004

Jay West wrote:
> Jochen wrote...
>
>> Those Promise "RAID" cards don't do hardware RAID. They handle RAID
>> entirely in software, by there own BIOS for booting / DOS and via a
>
> I don't *THINK* that is true, at least as a generalization. There may be
> some low end cards from promise that don't really do hardware raid, and
> there may be promise chips built into some motherboards that don't
> really do hardware raid, but - my experience is that most of their ata
> raid cards actually do hardware raid. Can someone clarify for sure?

   I haven't seen any Promise chip that does hardware RAID. I have a
simple rule of thumb - if I define a LUN in the RAID BIOS and my OS sees
the physical member disks, it ain't RAID. All the Promise models we've
tested or I've heard feedback on do exactly what Jochen says.

>> As you are running FreeBSD: What about vinum(4)???
>> The machine should be fast enough to handle RAID1 in software. No
>> problem with the Promise BIOS stuff, no cost for an extra PCI card.
>
> I won't do OS-land raid. Doing any raid level in the OS is simply...
> brain dead. For the same reasons that I refuse to use a WINmodem in a
> windows machine. It's inherently bad engineering to waste/degrade the
> main systems cpu for this kind of thing.

   I would agree with you if the server was a SPARCstation5 or
something. As you said yourself, we've got cycles to burn here.

   Actually, I *did* agree with you for a long time, for almost exactly
the same reasons, but was coerced - I like my job and the client's
always King - into using Linux software RAID1 a couple of years ago.
The last time I logged into that box it had over 600 days uptime, and we
have several production machines of our own running RAID1 in software.

>> If you want real hardware RAID look for a 3ware card.
>
> I'll look at 3ware, but like I said I was under the impression many
> (most) promise cards did do real hardware raid.

   Promise says they do, and proves it by the fact that there's a RAID
BIOS setup. They lie, pure and simple.


        Doc
Received on Sun Oct 10 2004 - 12:47:25 BST