On 9/13/06, Richard Elling <[EMAIL PROTECTED]> wrote:
>> * Mirroring offers slightly better redundancy, because one disk from
>> each mirror can fail without data loss.
>
> Is this use of slightly based upon disk failure modes? That is, when
> disks fail do they tend to get isolated areas of badness compared to
> complete loss? I would suggest that complete loss should include
> someone tripping over the power cord to the external array that houses
> the disk.
The field data I have says that complete disk failures are the exception.
I hate to leave this as a teaser, I'll expand my comments later.
BTW, this feature will be very welcome on my laptop! I can't wait :-)
On servers and stationary desktops, I just don't care whether it is a
whole disk failure or a few bad blocks. In that case I have the
resources to mirror, RAID5, perform daily backups, etc.
The laptop disk failures that I have seen have typically been limited
to a few bad blocks. As Torey McMahon mentioned, they tend to start
out with some warning signs followed by a full failure. I would
*really* like to have that window between warning signs and full
failure as my opportunity to back up my data and replace my
non-redundant hard drive with no data loss.
The only part of the proposal I don't like is space accounting.
Double or triple charging for data will only confuse those apps and
users that check for free space or block usage. If this is worked
out, it would be a great feature for those times when mirroring just
isn't an option.
Mike
--
Mike Gerdts
http://mgerdts.blogspot.com/
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