[lug] RAID under Linux

[Nate Duehr]

On Fri, Mar 23, 2001 at 02:38:58PM -0700, J. Wayde Allen wrote:
> 
> Has anyone tried using software RAID under Linux?  If so, how well does
> this work?
> 
> I'm setting up a new server for my lab and was thinking about trying
> it.  Basically, I'm wondering if there are any words of wisdom or gotchas
> that I should be aware of?

Works well.  Have used it only under 2.2 kernels.  

I must say I'm happier with both the setup and the performance of
software RAID than I am with the performance and setup of a PERC-2/SI
hardware RAID controller in one of my Dell 2400's at work.

Agreed with other's who've commented, it won't buy uptime -- just
redundancy.

A friend of mine who recently needed similar but not quite the same
redundancy put two identical 30+ GB drives in a machine but elected NOT
to RAID them.  He simply "dd"'s one drive to the other nightly.  That way
as he puts it "when I mess up, I'm NOT mirroring bad data to the backup
drive and I can simply either swap them or copy the data back from the
other and start again losing only a few hours of work."  

I kinda like that for a workstation.  Yes, it has problems, especially
while the machine's still up and running in multiuser mode, but so far
he's been happy with it.

Back to software RAID, I watched it pretty closely for serious
performance bottlenecks and didn't see too much in the way of even
noticing that it was there and doing its thing.  I never did find a
great way to MONITOR the status of the RAID, but my understanding is
that it was right there in /proc under my nose the entire time.

-- 
Nate Duehr <nate at natetech.com>

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