Subject: Re: RAIDFrame in Production Use
To: Caffeinate The World <>
From: Manuel Bouyer <>
List: netbsd-users
Date: 04/12/2003 21:47:36
On Thu, Apr 10, 2003 at 04:23:45PM -0700, Caffeinate The World wrote:
> If you have experience in using RAIDFrame in production, I'd like to
> know what your thoughts are. 

I use it on a NFS server since 1.4P days: alpha ds20, 20 disks over 4
SCSI channels at that time. It's now 30 disks over 6 SCSI channels.
I use only raid-1 (on said server, I have 20 disks in one raid-1,
and 10 in another one. Oh, and 2 in a third for system).
Since 1.5 all my servers have data on raid-1 (both IDE and SCSI disks).

> I hear it is CPU intensive, how intensive is it?

It does eat a little bit of CPU, but it's acceptable. I run it even on
a Sparc IPX (40Mhz). 

> What do you use for hot swappables with NetBSD? Any power down
> necessary?

I don't use hot-swappable drives (I have raid-1 mostly to avoid data loss,
and to choose the time at which I'll power down the box to change the
drive). However, on the ds20, I build the raid in such a way that a whole disk
enclosure can be powered down without service interruption, so I could change
a drive by just powering down the enclosure, remplace the drive, power back up
and rebuild all the drives in the enclosure.
Unfortunably there's a bug in raidframe with raid-1 on more than 2 drives,
which cause data corruption if you rebuild a drive with more than one drive
failed, and you're writting to the raid-1. So I have to unmount the
raid-1 before rebuilding (rewriting parity on a live raid-1 doesn't cause
problems though).

> Which RAID do you use and for what application?

Only raid-1 in my case - raid5 is too slow for writes. It could probably
be used for mostly-readonly filesystems though.
I have raid-1 for all my servers: NFS/samba, mail/web/ftp/squid, print,
amanda, network monitoring via mrtg, etc ... 
This on alpha, i386 and sparc systems.

> Anyone using it on a database system like PostgreSQL or MySQL? Which
> RAID? What was it's performance with RAID added?

I have a mysql database on my www servers. But I didn't do any benchmarks.

Manuel Bouyer <>
     NetBSD: 24 ans d'experience feront toujours la difference