[OT] Dell PERC raid cards. Was: request for comments
jcoby at listingbook.com
Tue Apr 6 15:32:26 BST 2004
> As a matter of interest, would you have a link to anything that
> describes this issue? I've been using Dell PERC cards for *years*
> without any hint of a problem.
I thought I'd throw what I know into the mix:
Dell has 2 different types RAID chips: AACRAID and Megaraid(LSI). They
repackage those two basic types into the PERC controllers .
>From what I understand, the Megaraid driver is less than reliable. We have
three servers running on AACRAID (two 2450s and one 2650) that have been
plenty reliable -- not a single h/w failure, oops, or malfunction that could
be attributed to the dell hardware in 3 years. Most (if not all) of the
major Linux distros provide support for the AACRAID, and it generally just
We also have one 1750 with the PERC4/Di, based on the Megaraid chipset. It
was very difficult to install any distro of Linux on. Neither RedHat 7.3
nor Debian (stable/testing) had support in the kernel. I had to track down
an install module before it would work . Search google (groups), and
you'll find all sorts of stories like this, and some stories of array
corruption. There are also some reports of the Megaraid chipset being slow.
I get pretty decent performance out of it .
We're running the 1750 as the primary production webserver, and haven't had
any real issues that I could attribute to the hardware. It's only been up
41 days though. I'll be avoiding any poweredge with the megaraid chipset in
2. in addition to finding a module for the RAID controller, I had to grab
the network controller driver module from broadcomm as well -- there is no
support for it in redhat 7.3.
3. two runs of hdparm -t -T /dev/sda, a RAID 1 mirror
Timing buffer-cache reads: 128 MB in 0.38 seconds =336.84 MB/sec
Timing buffered disk reads: 64 MB in 3.46 seconds = 18.50 MB/sec
Timing buffer-cache reads: 128 MB in 0.29 seconds =441.38 MB/sec
Timing buffered disk reads: 64 MB in 0.45 seconds =142.22 MB/sec
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