I calculate...
18 usable inches in a 19 inch rack case. That's 45cm, using 9mm drives with a little air spaces, that's 45 drives per row. Multiply that by 6 rows that's 270 drives in a single 3U unit. That leaves plenty of room for a motherboard and a few terabytes of RAM.
So, 270 drives times 15 gigs is 4050 terabytes per 3U. That's 14 3U servers per rack. That's 56,700 terabytes of storage... or about 55 petabytes per rack.
The problem of course is... there's not a single SAN vendor which can cope with a crash with regards to RAM. So, if I have a write cache of 6TB and my server crashes... or I get an ECC errors... it's toast. Windows Storage Spaces is not too bad though with SoFS.
Biting the hand that feeds IT
