Hello All,
We're running a pair of FAS8020's with Flash Cache modules, SAS 600GB 
disks and DOT9.1P6 to serve two SVM's, one for an NFSv3 storage resource 
for our Xen VM farm and one for NFS/CIFS file storage for our users.
We currently run one SVM on one node and one on the other to avoid any 
impact from mixing IO loads on the cache modules. We also have two 
aggregates, one for the VMs and one for the file server.
We're getting tight on space and also getting tired of needing to 
withhold unallocated disks and hand them out as needed to each 
aggregate. Right now we have too much free space on one aggregate and 
not enough on the other. We're leaning toward using the system like an 
enterprise storage cluster is meant to be and migrating both to a single 
aggregate.
On the other hand, we've been bitten before when mixing different 
performance loads on the same gear, admittedly that was for a larger 
pool of very different loads on SATA disks in a SAN behind a V-Series filer.
We're not much worried about cache poisoning as long as we keep each SVM 
on each node. Our bigger concern is mixing loads at the actual disk IO 
level. Does anyone have any guidance? The total cluster is 144 600GB SAS 
10K RPM disks and we'd be mixing Xen VMs and NFS/CIFS file services that 
tend to run heavy on "get attr" reads.
Let us know your thoughts and if you need any more information,
Randy in Seattle