Subject: Re: ahc and raidframe questions
To: Chris Jones <email@example.com>
From: Greg Oster <firstname.lastname@example.org>
Date: 06/23/1999 14:48:22
Chris Jones writes:
> I'm in the process of setting up a machine with a RAID array hanging
> off an Adaptec 2940UW. In the process, I've discovered a few weird
> things, and I was wondering if anybody could comment:
> * Doing anything with the RAID array seems pretty slow. It took over
> two hours to initialize the parity information for a RAID5 array
> across three 9G disks. It's currently doing a 17GB newfs, and it
> looks like that will take about an hour by the time it's done.
Given that it's got to read 18 GB of data and write 9GB of data, it's going to
take a little while to re-write parity, even with fast disks... I'm not sure
if 2 hours is unreasonable or not, as I've never worked with a RAID set that
big with RAIDframe, nor have I used UW controllers/drives (yet). (I've thought
about how nice it would be, but that's it :) )
> This is an i386, 1.4 system.
> 2940UW with 3 Fujitsu 9GB UW disks
> hanging off it. It also has an on-board ncr and pciide.
> I haven't yet tried actually reading and writing files on the RAID
> array, because it's not done newfs'ing. But it may be that actual
> file operations will be pretty fast.
It could also be that the stripe width (or sectors per stripe unit) are
not optimal for those drives/your machine.