[volunteergrid2-l] Slashdot post

[Aaron Drew]

I do almost this exact thing but I send my zfs snapshots to s3. I
wholeheartedly second this recommendation! Beware of zfs failure cases
though. Things like copies=2 give a false sense of data security. I suggest
playing with intentionally corrupted devices first to learn your way around
the tools and their limitations.
On Apr 5, 2012 10:18 PM, "Eugen Leitl" <eugen at leitl.org> wrote:

> On Thu, Apr 05, 2012 at 06:08:14AM -0600, Shawn Willden wrote:
>
> > One comment here:  I've come to the conclusion that RAID5 is evil and
> > dangerous.  I've been meaning to write a paper on it for years but never
> > gotten around to it.  Assuming you back everything important up to the
> grid
> > it would be okay, but personally I use RAID6 for everything important.
>
> The failure mode in large, consumer (high unrecoverable error rate)
> unscrubbed (undetected bit rot) is that one drive falls from the array,
> and during rebuild/resilver either due to bit rot or uncaught error
> the second drive falls from the array, after which your data is typically
> toast.
>
> Higher RAID levels (RAID10, RAID6, raidz2/raidz3) will protect you
> from that. I would still recommend weekly scrubbing for consumer
> (SATA is consumer) drives.
>
> I recommend using zfs and raidz2 or higher in suitably designed
> arrays with weekly or at least monthly (for SAS) scrubbing for
> more or less important data. Notice that with zfs send you can
> easily replicate a consistent snapshot to a local or remote zfs
> pool, with a high peformance than rsync or unionfs.
>
> A good cheap hardware platform for that is HP N40L with 8 GByte ECC RAM
> and a Solaris derviate with napp-it. Same platform will also support
> FreeNAS, a FreeBSD distro supporting zfs (but less than Solaris
> derivates).
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