> > If you the choice to make again, would you buy another Network
> > Appliance, or would you get the biggest disk array you could
> > find for the same money? Why?
> *provided i needed RAID5*, that's a no-brainer. it's noticeably better
> than any of the other RAID5 offerings i've tried, and likely cheaper than
> RAID0+1 with anyone's discs and arrays.
Thanks for the kind words! However, lest anyone get too confused, our
filers use RAID-4, not RAID-5. Still parity and the same degree of
data protection, just on one disk instead of being interleaved amongst
all disks as RAID-5 does. The advantage of RAID-5 is that you can use
a traditional file system, designed for a single disk and not for RAID,
and distribute the parity workload amongst the disks instead of it
being focused on one disk. NetApp uses a file system designed for
RAID to avoid the parity disk bottleneck.
RAID-4 has the advantage of allowing you to expand the RAID group (even
by just one disk), and of using disks of varying geometry in the same
RAID group. RAID-5 requires all disks to have the same geometry and
cannot itself be expanded, though you can expand the filesystem by
concatenating an additional RAID group (not just one disk, and more
space is lost to parity).