[rescue] Any Minneapolis area listers ?

Patrick Finnegan pat at computer-refuge.org
Wed Jan 10 15:32:53 CST 2007


On Wednesday 10 January 2007 13:46, Jonathan C. Patschke wrote:
> On Wed, 10 Jan 2007, Patrick Finnegan wrote:
> > Hardware raid only adds expense, bugs, slowness, and makes it harder
> > to fix when the raid controller does something stupid.
>
> I've had exactly the opposite experience.  When I want my storage to
> work (which is, well, usually), I use a hardware RAID controller. 
> Using software RAID only adds bugs (more software layers to fight
> with), slowness (both in actual read/write latency and in consumed CPU
> time per storage transaction), and makes it nearly impossible to fix
> when the OS gets its metadata out of sorts.

What have you used for hardware and software raid?

I've used a AlphaPC164LX with a 600MHz 21164A, with 1GB FC-AL and FC-AL 
drives, and was getting 70MB+/sec read and write speeds on it, with 
Linux software raid set up to do an 11+1 RAID-5.

The $40,000+ IBM DS4500 we've got at work, at best performed at about 
140MB/sec write speeds, to a RAID5 setup.

Twice the speed, for 6-year newer hardware, and a much higher price tag 
is just not worth it, in my opinion.

It's really easy, with linux software raid, to blow away and 
re-initialize the metadata on the raid, without losing any data.

Running a broken and frequently-crashing E3000 in my office, I 
occasionally had to do this, when the machine overheated, and marked 
multiple drives "dirty".  Try and fix that sort of error with hardware 
raid, where you don't have access to the moving pieces.

Pat
-- 
Purdue University ITAP/RCAC       --- http://www.rcac.purdue.edu/
The Computer Refuge               --- http://computer-refuge.org



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