Re: RAID

[lsorense@csclub.uwaterloo.ca (Lennart Sorensen)]

On Thu, Nov 10, 2005 at 11:44:26AM -0800, lordSauron wrote:
> So with RAID 1 I'll get write-speeds like I only have one drive with
> no RAID, but with RAID 0 I'll get write speeds like I have umm... RAID
> 0...  but the read speeds are (effectively) the same, correct?

Well raid0 reads twice as fast since you only read half the data from
each drive, although theoretically you can make raid1 read half the data
from each disk too.  Not sure if this is usually done or not.

Raid0 certainly does write faster.

> True...  makes me wonder about the frequency of drive faliures.  Those
> who have experience: how often does that happen?  I've never had a
> drive fail in my life, but I'm your normal desktop user so my PC is
> off for about 8-16 hours a day.
> 
> Dang it, fate would have it that I should leave now, but I shall
> return (sometime later today, if fate does not conspire against me...)
> 
> Thanks for all your great help and I hope that I'll someday be able to
> repay you all in kind...

Well I have had many IBM hotswap scsi disks fail (9, 18 and 36G drives)
when I did sysadmin work a couple of years ago.  I was quite sick of
them really.

I have in the past seen many WD drives fail that were 500-1300M in size,
while I haven't had problems with current WD drives.  I have had an 80G
maxtor die without 8 hours of being installed in a machine (so it was
hardly even in use yet and no data was lost of course).  I have had a
bunch of IBM 20G drives fail (part of that series involving class action
lawsuits as far as I can tell).

Len Sorensen