Re: external SATA HD config/backup questions

Kyle Jones <kyle_jones@xxxxxxxxxxxxxxx> wrote:
> <baratunde@xxxxxxxxx> wrote:
> >
> > Here's the proposed setup of the main drives
> >
> > A) internal SATA system drive - 160GB (aleady exists)
> > B) Internat SATA low priority drive - 250GB (already exists)
> > C) (PROPOSED) external SATA for working, video editing, music etc -
> > 800GB (two 400GB in a Firmtek enclosure under RAID 0)
> >
> > I'm aneed a good backup solution for A and C, preferably using SoftRAID
> > 3 to mirror them on yet another RAID stripe.
>
> RAID 1 is best for high availability of data, not as a backup of
> data. Using RAID 1, if you make a mistake and delete something
> important it will be gone instantly from the mirror as well. If
> the OS has a filesystem bug and wrecks the filesystem, the mirror
> will be wrecked as well.
>
> Unless you need the high availability provided by RAID 1, I
> recommend having a mirror disk or mirror stripe, but not using
> RAID 1. Use CarbonCopyCloner, rsync or something similar to
> backup your files to the mirror once a day.

It's confusing reading for you to use the terminology 'mirror disk'
when you are referring to clone backups.

----

Yes, if you 'make a mistake' you've deleted the file on both.

But the claim that it's not a good backup solution is something I'm
not so sure of any more.

My system froze up a little while ago, I rebooted and SoftRAID reported
that it was rebuilding my mirror set, and that I could go ahead and use
it while it was rebuilding it. Both disks have HFS+ journaled FS's.

It's fixing its own backup.

While you are right that the mirror disk info still needs to be backed
up, I'm not so sure this isn't a decent scheme for now. It's not as if
the system tells you which filenames were damaged on a solo disk...

So, what would one do for a solo disk with unknown files lost and a
backup on external media? It looks like a very messy procedure compared
to an automatic mirror repair. The least messy procedure would seem to be to
load the backup onto a spare disk and run CCC or SuperDuper to fix - well,
there's that extra disk being used, may as well use it for a mirror in the
first place.

What do y'all think?
.

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