[Novalug] NAS Box using software RAID

[American Dave Kline]

On Mon, Jul 12, 2010 at 01:29:53PM +0000, Jeff Stoner wrote:
> On Mon, 12 Jul 2010, Jay Hart wrote:
> 
> > I'm standing up a new NAS Box (using FreeNAS) using matching 1TB Drives (total
> > of two drives).  System disk will be a USB flash disk.
> >
> > 1. What is the best combo to use for these two drives?
> 
> Mirroring for 1 TB of space, LVM for 2 TB of space. I suppose you could do 
> RAID 10 if you half each drive but I've not tried that.

RAID 10 (RAID 1+0 I presume) for two drives?

> > 4. What would be the best plan to use for a 2 drive RAID system?
> 
> You only have 2 options (in my mind) - striping and mirroring. As I said, 
> you might be able to do RAID 10 with some partitioning but it's not 
> something I've tested.

RAID 10 with partitions on two drives is possible (in Linux at least) but would be very sub-optimal.  You'll lose both
the write speed and reliability advantages RAID 10 can offer.

> RAID 5 with only 2 physical drives? Where are you going to write your 
> parity bits?

Three devices are required for RAID 5.

Regards,
-A. Dave