Using and Archive file in Navisphere/Unisphere Analyzer you could select all of the disks on a single bus and look at Bandwidth, then export the data into Excel and do a stacked graph.  The stack will show the total bandwidth for all of those disks which should give you a good idea what the entire bus is doing (should be equal).  Since each bus can sustain approximately 360MB/sec per SP you can compare the total BW to the 720MB/sec maximum.  If one SP is handling more significantly higher than 50% of the load then you won't be able to get to 720MB/sec though.
 Hi i have a question about how many normal (Spindels) drives you can have on each Back-End when you use EFD's As in H8046 WP on page 18 it's stated that the maximum recomendet EFD drives on each back end is 15 to avoid the bandwith limitation of the BE bus  Can this be understand so, if you have 15 EFD's on 1 BE then you cannot have any normal spindels, if the 15 EFS's is having a hard time, ore is the 15 EFD's the maximum if the rest of the bus is filled up whit normal spindels FC or SATA ? Anohter way to say it, can 15 EFD fille up an entire BE, so no one ohter disks can be on the bus ? Ofcourse depending on the load of the drives.  I think, if you have the maximum of 2Tb FAST CACHE (CX4-960) then you need 20 200Gb EFD's these must be then put on 2 seperate busses, 10 on each then how many FC drives can i have on the 2 BE's, in this case we must presume that these 10 EFD's on each BE are heavy loadet to fullfil the FAST CACHE load in a system whit a lot of Storage Pools whit many lun's.  And yes i know the limitation of how many EFD's each CX4 Model can support, it's fits whit 15 EFD's on a CX4-960 whit expantion pack. 120/8=15 EFD's  Regards Kenneth Hansen
Max EFD's pr Back-end/Bandwith