Ok assume you need 100 gig of storage :)

If your using LUNs and following Netapp best practices you need to allocate minimum of two times the space required to allow for overwrite reserve = 200 gig total

if your mirroring and want to keep snapshots, best practice is 20% (well thats the default = 220 gig total

Volumes have a 10% File System overhead = 242 gig total

242 gig is about what you get out out of a Netapp 300 gig disk after right sizing and disk overheads..so thats 1 data disk per 100 gig you need.

For every 14 data disks (or part thereof) you need to burn two parity disks (so if you need 100 gig of data only you need three disks)

Assuming your running plex mirroring (havn't looked up the conditions of the Guarantee but that sounds right) then you need another 3 disks (total of 6)

+ 2 spares (total of 8)

So with a shelf of 14x300gig Fibre disks you get to hold about 700 gig of data (8 disks for 100 gig + 1 disk per additional 100 gig)

oh, assuming your running high availablility (clustered controllers) then you loose another 3 disks out of the shelf for that (assuming Raid4 2 disk system volume and 1 spare which is kinda on the edge) so your 14 disks will hold only 400 gig of data

The numbers are a bit better if your using NFS as the disk access protocol

I do use and like NetApps for NAS storage but I always thought they would do better marketing their features rather than their price (and I thought they should get out of block based access alltogether)

My coats the one with the pocket calculator in he pocket