I originally went for RAID-5 a number of years ago (originally with 4x 1TB Drives) for the following reasons (in no specific order).
A single massive volume rather than several smaller volumes.
Redundancy without losing as much HDD space as RAID 0, or 10.
Better performance than a single drive.
I think those were its major selling points. Today LVM, drive pooling, etc. takes care of point 1; and single drive performance has improved (100MB/s sustained throughput for high-density platters last time I looked into it) taking care of point 3 in a 1Gb/s LAN.
Re: point 2 above, do you need any redundancy in a server that you only turn on to dump data to/from? RAIDs redundancy maintains availability, which is sort of moot if you're turning the server off.
Since then my data collection has spiraled out of control and I have far more data than I can backup. I have 2x 2TB backup drives, only one of which even has data backed up onto it, the other one is labelled "overflow 1", so essentially I have about 1/4 of my data backed up, some with no redundancy at all. I only turn my server on when I need to dump more data onto it, or get data off (less frequent ATM) this has as much to do with how I use it as to give as much protection to my existing data set as possible until I can afford to do a serious upgrade.
I've always understood RAID to be about up-time rather than safety ... the whole "RAID ≠ backup" meme someone trots our every time someone mentions RAID in a forum
. Small Net Builder's classic: Smart SOHOs Don't Do RAID
Only you can know how valuable your data is, but assuming it's all somewhat
valuable, I'd rather spend on backup than network file copy performance. Seconding what's already been suggested: I'd retain your current server as a backup target and build a new primary file server. I appreciate the goal of 100+ MB/s network transfers, but at the expense of backups?
For important stuff, I like the 3-2-1 backup mantra: keep 3 copies, on at least 2 different forms of media, where at least 1 copy is off-site. I have two low-powered servers, the D510MO music server I wrote about previously and an unRAID bulk file server. Neither can saturate my gigabit LAN. The unRAID server comes closest, but only for sustained reads (80MB/s from my WD10EADS, if I remember). Both are fast enough for my wallet. I picked unRAID for a variety of reasons, and I've been generally happy with it but it's definitely not for everyone (really slow writes, for one). The bulk of the unRAID server's data are rips of movies I own; those aren't backed up because a) I don't have the space and b) although I could re-rip them, I probably wouldn't miss most of them! But the unRAID server is the backup target for my music server. I have all the original CDs, but re-ripping, tagging and organizing my collection would take ages and drive me to (more) drinking. I take a 1TB USB drive off site with all my important data. My data set is much smaller than yours; I'm not sure how you'd implement such a backup strategy. Lots of externals, I suppose.
Smallnetbuilder's recent series on 10GbE NAS was interesting reading:http://www.smallnetbuilder.com/labels/10GbE
[off topic] I looked SSDs for our db server when we upgraded a few years back. At that time, SSDs were too new / untested for my boss to approve of. Our servers come from Dell, who's 5-yr next business day replacement warranty was more valuable than peak performance. In reality, RAID10 with 15k RPM drives is more performance that we can use. Our ERP software's client side application is quite possibly the worst piece of software I've ever used. It's mind-bogglingly stupid, but we're stuck with it. It's a bigger bottleneck than our db server's storage subsystem.
Fingers crossed ... [snip] ... for my house sale to go through
Good luck! My wife and I will soon be trying to sell our house. I'm not looking forward to it.