[NBLUG/talk] More hard drive problems

[Lincoln Peters]

On Oct 3, 2005, at 10:55 AM, Kyle Rankin wrote:
> If you did want to change filesystems, basically you'd need at  
> least 2 new
> drives.

That's what I was afraid of.  I'd need to get my hands on 2 new hard  
drives, each one being at least 300GB, to change filesystems.  That's  
not likely on my budget.

> You'd set up a degraded RAID5 on the new drives, format with the
> new filesystem (I'd recommend XFS) and then copy all the files  
> over. Once
> they are copied over you can hot-add the last drive to the array  
> and have
> it sync.

Actually, I think I can see a way that I could make this work with  
just one new hard disk that's at least 250GB.  I'd detach one of the  
three disks from the existing array (not applicable to my situation  
since one is already detached), create a new degraded RAID5 array as  
per your suggestion, copy everything from the old RAID array to the  
new one, shut down the old array, then attach one of the two  
remaining drives from the old array to the new one so that it can "un- 
degrade" itself.

The only possible problem I see with this plan is that if another  
disk in the old array failed while copying, I'd be in for some major  
headaches (probably irreparable data loss, too).  If a disk in the  
new array failed while rebuilding, that would probably result in  
similar major headaches (since the old array would be down to one  
disk, I wouldn't be able to rebuild it in this scenario).  Of course,  
it's not as if being struck by a comet wouldn't cause even worse  
headaches, so maybe I'm just worrying too much.

Hmmm... depending on which parts of the damaged hard disk are  
actually damaged, I might even be able to use *it* as the fourth disk  
for the above conversion process.  Or maybe I'm just going to end up  
creating more problems than I'd end up solving.


Lincoln Peters
lmpeters at mac.com