Qsan provides a monthly updated compatibility matrix for all customers to check which disk models have been tested and verified on which Qsan storage models. The compatibility matrix is downloadable from Qsan partner portal. We also suggest using Enterprise level disks on all Qsan products to ensure the durability as most of the desktop drives are aredesigned for 24x7 usage and might also have durability issue in multiple disks environments with stronger co-vibration factors.
The S.M.A.R.T. is a monitoring mechanism on SATA disk, a SAD disk uses its own reporting mechainsim for disgnostic purposes. Thereofore so it is normal that on SAS disk you won't see any S.M.A.R.T. values, though some basic information such as disk temperature can still be reported.
No, for now the Qsan NAS products don’t support USB external storage. If the user needs more space from Qsan NAS, TrioNAS LX series support JBOS expansion units for adding more disks to the system.
On QSAN NAS, all NAS models support networking versopn UPS, but for U4/U6 series, they support serial version UPS. On SAN, we support three snmp version, serial, networking and megatec UPS. 
Qsan NAS support SNMPv2c version, SNMPv2c comprises SNMPv2 without the controversial new SNMP v2 security model, using instead the simple community-based security scheme of SNMPv1
Please login in webui, opening the Maintenance page and click the download in the left part of the page, then the user can click the download system for SNMP MIB file.