[NTLUG:Discuss] Software Raid ( was Small NAS box ideas?)

[Chris Cox]

Fred James wrote:
> So that brings me back to the question I've always wanted to ask:
> Isn't a mirror (wherever, or however) only a possible protection against 
> lost data due to a hardware failure?
> Is there any mirror that would know the difference between "good" and 
> "bad" data?
> Have missed something here?

Valid question.  RAID handles only certain types of
failures.  Obviously file system corruption cannot be covered
by RAID.  In a mirrored solution the OS mistakes are
mirrored.  However if a drive goes out (HW), it generally doesn't
talk to the other drive :-) .... so you can usually recover
from something like that.

Some would argue that you need every drive on its own controller
to avoid issues (for instance, some would argue that it is bad
thing having more than one drive on a SCSI bus).

Obviously redundancy can be taken to various levels....
as high as you can imagine.