[2639] in linux-scsi channel archive
Re: Dell PowerEdge/American Megatrends MegaRAID
daemon@ATHENA.MIT.EDU (Louis Mandelstam)
Fri Oct 17 03:26:28 1997
Date: Fri, 17 Oct 1997 09:22:43 +0200 (SAT)
From: Louis Mandelstam <lma@sacc.org.za>
To: Linux SCSI List <linux-scsi@vger.rutgers.edu>
In-Reply-To: <199710162351.AAA22973@irvine.intelligent.co.uk>
On Fri, 17 Oct 1997, John Robinson wrote:
> Is there, or is anyone working on, a driver for the American
> Megatrends MegaRAID controller? I've been given a Dell PowerEdge
> 4100/200 which has one integrated in it, plus two aic7xxx chips and 5
> removable discs; it seems a shame to have to run RAID in Linux since
> there's a hardware controller with cache etc...
>
> Or is this another controller (like the Adaptec 3985?) which just
> lends a hand to doing RAID in software?
Running a Dell PowerEdge SP5166-2 here as follows:
- Red Hat Linux 4.1 for x86 - kernel 2.0.27
- Dell RAID: (from /proc/scsi/scsi)
Attached devices:
Host: scsi0 Channel: 00 Id: 01 Lun: 00
Vendor: Dell Model: Drive Array II Rev: A12
Type: Direct-Access ANSI SCSI revision: 01 CCS
..with 4 x Seagate Hawks
- also has: (from /proc/pci)
Bus 0, device 15, function 0:
SCSI storage controller: NCR 53c810 (rev 17).
Medium devsel. IRQ 10. Master Capable. Latency=64. Min Gnt=8.Max
Lat=64.
I/O at 0xf400.
Non-prefetchable 32 bit memory at 0xfe000000.
Now, the RAID (Dell SCSI Array or DSA as they call it) runs off its own
dedicated SCSI controller sitting on the machine's EISA bus. I had a hard
time figuring out that chip this controller was based on, but from what I
could tell on Dell's web site, it's an Intel i960 RISC CPU, so I haven't
been able to find Linux kernel support for it.
HOWEVER - it also supports an AHA154x emulation mode, and I'm using in
that way currently. I haven't been able to find out what kind of
performance hit this induces, but I do find that the RAID's speed has been
disappointing.
It does give me full hardware RAID however, transparent to the OS, with
device hot-swap ability, so it does help a lot. I think I'd have a
preferred a CPU-only box with an external SCSI RAID system, both
rackmounted, but that'll have to wait until one day when the system gets
upgraded or I install another one.
I also would have liked to be able to get the OS to detect alerts from the
hardware (RAID as well the temperature and fan speed monitors) but thus
far nobody has been able/willing to tell me how/if this can be done.
Regards
---------------------------------------------------------------|-----|--
Louis Mandelstam Tel +27 83 229-0712 Symphony /|\ /|\
Linux systems integration http://sr.co.za Research { } { }
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