building a RAID system - 8 drives

Joshua Baker-LePain jlb17 at
Thu Oct 9 09:26:45 EDT 2003

On Thu, 9 Oct 2003 at 7:02am, Jeff Layton wrote

> spare. Works great! It's saved our bacon a few times. I've
> wanted to test hot-swap with 3ware controllers, but have
> never done it. Has anyone tested the hotswap capability of
> the 3ware controllers/cases?

Yes, and it works just as advertised.  To add my $.05 to the discussion, 
I'm a pretty big fan of the 3wares -- I currently have 5TB of formatted 
space (with about 2TB of data) on them.  I have two servers with 2 cards 
and 16 drives in them, and one with 1 card and 8 drives.  On the two board 
servers, I run the 3wares in hardware RAID mode (R5 with a hot spare), and 
then do a software stripe across the two hardware arrays.  With the boards 
on separate PCI busses, this lets the stripe go faster than the 266MB/s 
that the boards are limited to (these are 7500 boards, which are 64/33).

3ware's 3DM also lets you monitor the status of your arrays (it's almost 
too verbose, actually), and do all sorts of online maintenance.  Not 
having used mdadm much, I can't really compare the functionality of the 
two.  A couple of nice features of 3DM is that it lets you schedule array 
verification and background disk scanning, which can find problems before 
they affect the array.

I'm not sure what cases or backplane these systems use (I bought 'em from 
Silicon Mechanics, who I highly recommend), but the hot swap has always 
just worked.

If anyone's interested, I have benchmarks (bonnie++ and tiobench) of one 
of the 2 board systems using pure software RAID as well as the setup 

Joshua Baker-LePain
Department of Biomedical Engineering
Duke University

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