Raid 0 + 1

[Thomas Hurst]

* Kevin Thompson (antiduh at csh.rit.edu) wrote:

> Now we're going to pull together the d partion on each drive, create
> pairwise stripes, then mirror the new stripes together.
>  gstripe label -vh -s 131072 st0 /dev/label/geom0s1d /dev/geom1s1d
>  gstripe label -vh -s 131072 st1 /dev/label/geom2s1d /dev/geom3s1d
> 
> We should now have two new devices '''/dev/stripe/st0''' and
> '''/dev/stripe/st1'''. Now mirror those two devices to create our final
> device that will next be used for the rest of our filesystems:
>  gmirror label -vh gm0 /dev/stripe/st0 /dev/stripe/st1

Er, shouldn't you be doing this the other way around?  Make two mirrors,
then stripe across them.  IO performance should be identical in the
normal case, degrade less with a single disk failure (since only one
disk drops out of the array instead of an entire pair), and it'll be
more likely to survive a two disk failure.

-- 
Thomas 'Freaky' Hurst
    http://hur.st/