For a new server, is it a bad idea to use Incremental Backups AND RAID 5?

[dag10]

I'm building a new server for myself to replace the Best Buy -bought Dell PC I've been using as a game/webserver for a couple of years. The new server will be lasting me through college hopefully (I am in 10th Grade now), and it will host my projects' GIT/SVN repos, websites (>1), MySQL databases, and personal files as a personal "cloud" storage.

Here's what I'm planning to do.

I'll buy 4 HDDs, each being 2TB. I'll have them running on RAID 5 to protect my server from immediate HDD failure. My understanding of RAID5 is somewhat loose, but basically with RAID 5 (due to its distributed parity) if one drive fails, the system will still be able to "read" and "write" to that drive due to the parity information, albeit very slowly. I plan on using Fedora LVM for managing the RAID.

Then with the Three 2TB HDDs left, I'll take the first two and split them up into two 1TB partitions, which leaves me with 4 1TB disks and 1 2TB disks for the system to use.

On the first disk I plan on storing the OS and all software. On the second disk I plan on storing /var, which will hold my websites and databases. On the third disk I plan on storing game servers (CS:S, GMod, TF2, Minecraft, et cetera), and on the fourth disk I plan on storing personal files. The fourth disk will be my "cloud" storage (1TB).

So on the final 2TB drive I plan on using for incremental regular backups of system and software config files, my websites, databases, gameservers, and personal storage. I realize that 2TB might end up being too small eventually, but it's fine for now. You see, the reason I want incremental backups is to revert files (like config files) to previous versions. The RAID is just to keep the server running immediately if a disk fails.

OR, another thing I could do would be to have the 4 2TB disks running in RAID 5 just be the things I described above but without backups, and then have an ADDITIONAL 3TB disk outside of the array purely for backups. Then again, if the backup disk fails, I lose all past versions of my files.

That's it. I realize I have said multiple [highly] laughable things. But bear with me, because I am relatively new to this and I want to make the most informed decisions. So in the midst of your laughter, it'd be appreciated it you could correct me. Thanks!

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Oh, I'll post my Motherboard and CPU specs too.

[list]
[*][url=http://www.newegg.com/Product/Product.aspx?Item=N82E16813131658]Rampage III Gene[/url]
[*][url=http://www.newegg.com/Product/Product.aspx?Item=N82E16819115225]Intel i7-930[/url]
[/list]
Explanation: I realize that the motherboard is meant for gaming and overclocking. I'm using these parts because [i]I already have them sitting around[/i]. It's a long and highly irrelevant story, but just know that in my bedroom I have these two parts already. There's no sense buying more server-appropriate parts just for the sake of it.

[Van-man]

[url]http://zfs-fuse.net/[/url]
And put the disks you intended to raid5 in RaidZ instead
[url]http://en.wikipedia.org/wiki/Non-standard_RAID_levels#RAID-Z[/url]
A little info on it, though I'd recommend doing some more research on ZFS and ZFS through FUSE before doing anything.
[url]http://en.wikipedia.org/wiki/ZFS[/url]