Re: NAS Remote Side of a Mirror

On Mon Oct 05, 2009 at 08:37:37AM -0700, adfas asd wrote:

I'm looking at setting up my RAID mirrored array so that one side of
the mirror is in the HTPC and the other is NASsed in the garage, in
case of theft or fire.

I am concerned about the boot process though, as the NASsed side will
not be available until the network comes up.  Will the array be able
to be patient for that and include that side once it comes up, and run
not degraded?

The network can be brought up from within the initrd, so there's no need
for the array to wait (that's even more trivial if you just have /home
on the array as you suggest below).  Alternately, you could use
write-intent bitmaps, in which case the resync should be very quick (you
may want these anyway - depends how reliable the network connection and
NAS is).

What if I lose my local side of the mirror?  Is failover possible to
the NAS side?  (Assuming a separate boot disk with everything except
/home, which is on the array)

Yes (providing you have the array set up properly so the remote holds a
complete data copy).

The only other technology I am aware of which can remote drives at
distance is fibrechannel, and that's too expensive, so it seems I'm
stuck with GB ethernet.  Are there in fact any other options?

Not that I've used, no.

Is it possible to bring up ethernet early in the boot process with
initrd.img?

Yes - this is pretty common for network booting.

Has anyone actually done any of this?

I've not anyway.

Cheers,
    Robin
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