Hello.

I'm planning to modify my fileserver quite a bit and have some questions. My current plan is following (RAID5 arrays are done using Linux software RAID):
http://img209.imageshack.us/img209/8481/raidplankt7.png
1) Should I use RAID0, LVM, EVMS or something else for the main storage? As far as I'm aware, RAID0 would be faster, but EVMS/LVM would allow me to add new arrays in future. Anyone know how big the performance hit is?
2) At which level should I do encryption (current plan is to do it for RAID5 arrays) both performance & security wise?
3) Should I make
a)4x5GB RAID5 arrays
b)1x20GB RAID5 array that is then split to four volumes
that are then made available thru iSCSI?