Which better - PERC 3/DC or 3/Di?

Hubbard, David dhubbard at dino.hostasaurus.com
Mon Nov 26 06:56:00 CST 2001

The Adaptec cards are great if you want to get 5 MB/sec writes
out of $3000 worth of 10,000 rpm disks!  Seriously, they
are that good!!  :-)

I wish I had a way to rip the on-board Adaptec RAID out of my 2400's...


-----Original Message-----
From: Ed Martin [mailto:ed.martin at iop.org]
Sent: Monday, November 26, 2001 7:02 AM
To: linux-poweredge at dell.com
Subject: Which better - PERC 3/DC or 3/Di?


I was wondering which of the PERC 3/DC and the PERC 3/Di was considered
"better" for Linux?

The 3/Di (and 3/Si) are, I believe, Adaptec controllers built into boxes
like the PE2450/2550 and enabled for a low cost.  The PERC 3/DC (and 3/QC,
3/DCL) is an AMI add-on card which can be added to most PE servers.  (I know
this is repeating the obvious, but I want to make sure I get it right!)

My criteria for determining "better" is roughly, in order:
1.  Reliability
2.  Performance   (we like RAID 10, or failing that RAID 5)
3.  Managability
4.  Cost

I have previously formed a preference for the AMI/MEGARAID controllers, but
am wondering if this was the right choice.  I rated it better on performance
and managability, and although more expensive this is less of an issue for
me.  I also wasn't very impressed with the afacli utility;  megamgr seemed
easier to use to me.  But the 3/Di now includes batter cache I think (and so
cached writes are safer) and it seems from reading http://domsch.com/linux/
that the adaptec driver is now included in the standard kernel.

A little background, in case it is relevent:
I should add that we always run the Dell version of Red Hat Linux.  And that
I prefer not to build kernels ourselves, or anything particularly advanced.
(Anything to reduce the hassle factor!).  Currently we have a mix of
PE1550s, 2450s, 2550s and a 6450.  We run Dell Red Hat Linux v6.2 (SBE2?) on
our live servers, and have v7.0 and v7.1 on dev/internal boxes.  RHL v7.2
looks very attractive and pending testing I am hoping to migrate to this on
most servers soon.  It will also be our first choice for new servers.

Apologies if this has been asked before.  I did a quick search on the
archives first, and found discussions about RAID controllers, but not quite
an answer to the above.

All comments / advice is very much appreciated.



PS.  Matt - if you happen to read this - I wished to add that
http://domsch.com/linux/ is a really useful site.  I only just found it and
wish I'd come across it months ago!  It spells out stuff I'd had to spend
time figuring out for myself, and adds lots of info which was new to me.
Thanks.  :-)

Ed Martin
Head of Systems Technology and Support
IOP Publishing Ltd
Dirac House, Temple Back
Bristol  BS1 6BE
ddi: +44 (0)117 930 1102
www:  http://www.iop.org

Institute of Physics
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