[K12OSN] [OT] Firewire or USB2 in a softRAID setup

Les Mikesell les at futuresource.com
Fri Jul 29 16:49:42 UTC 2005

On Fri, 2005-07-29 at 09:52, Shawn Powers wrote:
> Shawn Powers wrote:
> > (2) 300GB drives internally (IDE)
> > (4) 300GB firewire drives
> > (2) 300GB USB2 drives

I've been trying to make RAID1 work between an internal 250GB IDE
and an external firewire for ages.  It seemed solid on FC1 with
the 2.4 kernel but then it was a manual process to modprobe the
device to get it detected before adding to the raid.  I've switched
to FC3 and now the device is detected automatically but I haven't
been able to keep it running more than a day at a time with the
raid active.  Either errors on the drive make it fail and be
dropped from the raid or the machine completely crashes.  The
reason I want this is so I can keep offsite copies of my
backuppc archive by periodically swapping drives.  It has been
working well enough that I can connect a disk, sync the raid
and then disconnect, but isn't reliable enough to leave active.
I have a compatible backuppc setup on my laptop and can plug the
drive into it with USB2 and restore things. If I have time to rebuild
the system before the firewire/sbp2 drivers are fixed I'll probably
put LVM on the internal drive and just copy snapshots to the external
drive instead of doing a raid mirror.

> Hmm... just got this link from someone.  Maybe I'll rip the drives out 
> of the enclosures, and just do this:
> http://www.serverelements.com/naslite.php

I don't think that setup has any authentication.  If you just want
a bunch of shared disk space, install the Centos-based k12ltsp
version on a separate box for the server. 

> I worry about fault tolerance though.  What happens if a drive fails in 
> a JBOD configuration with software raid?

With RAID5, things slow down.  With RAID1 you don't really notice the
difference.  Either way when you add a working drive back to the
raid with the mdadm command it will resync and with hot-swap drives
you don't have to stop.  If you don't need portability, you should
probably just get a 3ware raid controller and move the drives to
a different enclosure.  If you do, you might be better off with
SATA and a hot-swap SATA case.

  Les Mikesell
   les at futuresource.com

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