2. 8-8 is beneficial only with very large LG's, or with very fast disks. Can the disk provide more than 4gbs of throughput? Then 8-8 might help. Do you have 200+ LUNs in the LUN group (max raised to 254 in DOT8.2)? Then 8-8 might help.
3. Can you clarify? I don't understand the question.
4. If you had 2 LGs, then generally half the LUNs from LG1, and half from LG2, would make up a single aggr. So that the aggr is spread across both groups of LUNs.
OK, this explains why I gave you a wrong answer in the other thread. I think I meant to reply to this message.
Will you be using virtual pools on the AMS? Or traditional RAID groups?
If traditional, then 5+1 RAID5 on the 300g give you 5 RGs, ~1.5TB each.
For the 600g drives, 5+1 R5 gives you 40 RGs of ~3TB each.
For the SAS drives, I would create ~1.5TB LUNs (1 LUN per 300G RG, 2 LUNs per 600g RG) That would give you 85 LUNs to split between at least two aggrs. Note that to avoid spindle contention, no aggr should have more than one LUN from any given RG.
For the 7K drives, I'm guessing 6+2 RAID6, but would defer to the storage admin. I'm going to assume these disks will not have performance as a foremost requirement. I would create 4 LUNs per RG @ ~3TB each (16RGs, 64 LUNs). Ideally making 4 aggrs. But if performance doesn't matter, then fewer aggs would probably be OK.