10TB Raid 6 for £1000?

[nry]

I currently have a 6TB file server with all drives running as JBOD. What I could like to do is build up a raid array with a minimum storage space of 10TB, I have been looking and like the idea of using Raid 6 simply due to the fact I can have two drives fail on me.

Now the problem is can I do what I want for around £1000, I know this is a primarily a USA forum but don't really know where else to get advice regarding a potential raid setup.

I have been looking into RAID controllers etc but not too sure what would be best. Was also looking at getting a lower port raid controller and the HP Expander card, as there around £240 over here. As I am guessing in a years time I will no doubt be adding additional drives!

I should be able to source some 2TB drives for around £90 each, the questions I have:
Can I use the eco drives (5400rpm) in a RAID setup? As I have seen some comments raised about setting the TLER on the drives?
Do I need a backup battery for my raid controller?
What cheap raid controller (but decent) would work with the HP expander card?

Current spec:
# Akasa Infiniti tower
# Corsair 650w PSU
# GA-MA74GM-S2H (mATX)
# AMD 5050e 45W CPU
# 2GB OCZ PC6400
# LG BluRay reader/writer
# 120GB 2.5" 7200rpm 16mb Samsung System/Boot Drive
# 2x RaxMax RM-223 Drive cages
# 3x WD 1TB GP Grives
# 1x Samsung Spinpoint 1TB
# 1x Seagate 7200.11 500GB
# 1x Seagate 7200 1.5TB
# Pinnacle 3010IX Dual DVB tuner
# Sil3114 4 Port PCI SATA card

for those who care...a picture of it

 

[randomlychosen]

You don't need an expander card for 10TB. An areca 1220 is 8x2TB which is about 10TB.

I would get an areca 1680i or 1680x for now and get your 8x2TB drives. Later you can add an expander card if you wish.

8x90 is 720 though, leaving only 280 for your raid card, and I think an areca card is just slightly more than that. But it's close.