Re: Backup--OT

[Harry Binswanger hb@xxxxxxxx]

> > Really? I haven't seen incorrect copying for decades.
> Then you probably haven't been looking for it. Incorrect copying is hard
> to spot when the OS or program does not report it. You just assume that
> your 100GB of user files is perfectly copied in the absence of any notice
> to the contrary.

Absolutely right! You caught me out.
> here are a few laptops with space for two drives and with hardware RAID
> capability
I have an extra drive in the port replicator, which the system treats as
internal
> but these are growing scarce. For a laptop that will permit two disk
> drives but that does not have a hardware RAID controller, either MacOS or
> Windows will do software RAID 1.

REALLY?! I knew Mac does, but what is the Win program for that?
> Performance hit with hardware RAID can be negligible.
> Running a system from an external drive without loss of speed would
> require a lot of high-end hardware and specialist intervention. I would
> think a Thunderbolt connexion would help.
> RAID 1 itself is not a perfect guarantee against data corruption - - see
> the Wikipedia RAID article which raises a number of important issues. (And
> note that while the simultaneous aging of mechanical hard drives is
> raised, the simultaneous aging of SSDs is just as likely to bring problems.)
Yes, that was scary. OTOH, it can't be *that* simultaneous! It's not that
C: and D: are going to fail within a couple of seconds of each other.
External raid boxes give you a notice of failure, so you can act. I wonder
if Windows software does that.
> In sum, I feel that any collection of personal data at any time will
> inevitably reflect some data corruption. I think the best defense is to
> hold time capsules: periodic backups on M-Discs DVDs or blu-rays. If a
> file is found to be corrupt in 2014, it may be possible to find an
> incorrupt version on, for example, a 2012 M-Disc. (Or even, if you're very
> lucky, conventional optical media.)

Unneccessary. See my recent post about Dropbox with "pack rat."
--Harry