[EMAIL PROTECTED] wrote:
>
> I know it has been done to death, but I really need some feedback
> on this topic.
>
> My proposed platform is a Dell Poweredge system, and they come
> with the AMI Megaraid controllers (16mb cache). I am planning on buying a
> 2xPIII 450mhz box, and I am trying to decide whether the advantages of
> hardware raid offset the additional $800-1000 (Canadian dollars) for the
> card.
>
> The biggest thing that I need is stability and useability; I know
> RAID-1 under Linux is very stable, as we have been running on such a setup
> for nearly a year now, with no probs. I have noticed however that there
> seem to be issues with hotremove/hotadd/hotswapping (list traffic lately).
> This box does not have a dedicated full-time sysadmin, and as such needs
> as little baby-sitting as possible - meaning that when I need to use
> hotswap capabilities, I need them immediately and I do not have a pile of
> time to 'fiddle' with kernel patches and re-compiles.
Let's see if my experience helps any...
I was using Linux software RAID (striping) and was vey impressed I
basically got exactly the max throughput I could expect. My complaint
was that it was hard for me to setup (tools shipped with RedHat 6.0
didn't agree with the kernel I was using) and that from kernel to kernel
the software RAID may or may not work.
Recently I picked up an AMI MegaRAID 428 controller cheap on eBay. Big
huge ugly thing... the RAID side of things was easy to setup but the
Linux drivers do not get along with my Narrow devices being on the
MegaRAID controller. My RAID performance is basically identical to the
Linux software RAID performance except that the CPU overhead is 1/10th
to 1/20th as much. Now writes are a different story and until I get more
RAM in my RAID controller (I have 8megs) I'll probably change it to do
write-through instead of write-back as writes seem to hiccup when
writing a large amount of stuff. The megmgr program AMI provides is
pretty cool too... can play with things on a running system.
So basically I see Software RAID as more flexible but possibly more
volatile. Performance for me was about the same if you disregard CPU
use.
Brian Macy
