Ok, so I have 2 Dell R710, twin 6 core Xeon w/HT, 16GB RAM, FC HBA acting as fileservers running Server 2008 R2
I have just purchased a Dell FC SAN made up of:
24 x 600GB 15k SAS drives
The MD3600f connects into my SAN switch, along with the 2 file servers. The MD1200 connects via dual 6Gbps SAS into the MD3600f.
The File servers hold network homes for around 2000 users (mainly macintosh, so quite a read intensive workflow). We have about 1200 devices.
FS1 = ~1000 students roughly 2TB
FS2 = ~1000 students roughly 2TB
How should I configure my storage to suit this environment. It needs to be fast - we were using a sata based system before, but it couldn't deliver the IOPS we required, hence the new SAN.
Now the questions:
Should I have one raid 10 array per server, or one large raid 10 array split into luns per server?
Should I separate homes and profiles onto different luns, or physical disks - we do have some windows users too.
I only initially require about 4TB (after RAID and formatting) but this will grow as i move other users over.
One RAID vol with multiple LUNs would allow each of your servers access to the highest possibly IOPs from the box - however, they could then be fighting over resources if both servers are hit hard at the same time. If you have 2 RAID vols, then you'll be guaranteeing the IOPs for each server (as long as the SAS and FC bits can handle it), but you'll get less maximum. It depends on how your data is structured above, and what sort of loads you see at logon and during lessons (does one server get hit hard, and the other have it easy, then they swap as different year groups are in and out of computer lessons, or do you have balanced usage across the 2). I'd probably lean towards to a single RAID10 to provide maximum possible IOPS, and then manage data at a LUN level to balance loads.
As far as separating profiles and home dirs across LUNs/disks, I don't think I'd bother - your profiles will only really be hit at logon and logoff, so shouldn't be being used whilst the home dirs are (ie during a user session).