EVO is compatible with APC uninterruptible power supplies. You can use any compatible APC Smart-UPS model that supports USB monitoring and provides sufficient runtime for your requirements (excludes all models in the Back-UPS family).
For selecting an EVO-compatible UPS, the typical unit of measurement is VA (volt amps). This is a combination of volts and amps, and is a way to measure the load capacity of a UPS.
In most situations, you can use a maximum figure of about 1500 VA for a fully loaded 16-bay EVO. In reality, the load is typically somewhat less, but it's always good to have a little extra headroom when spec'ing out this device. It means that you'll get a longer run time if the system switches to battery power. That's why we like to spec the 2200 VA units for EVO. Refer to the EVO Models & Specs page for more information on power load for various EVO systems such as the 16 bay, 8 bay, and Prodigy.
If you have an EVO expansion chassis, it can be powered by the same UPS that operates your EVO head unit, provided there is adequate capacity. Any additional load on a UPS will of course decrease the run-time while operating from the battery. In the event of power outage, the EVO Base unit performs monitoring of the UPS, provided it is a compatible APC model. Since all motherboard and RAID controller components are housed in the EVO Base unit, the Expansion chassis simply follows along. It is not a problem for the base unit to initiate a shut down when UPS battery capacity dips below the preset threshold. It will simply shut down and the expansion chassis will run until the battery is depleted. This does not negatively impact the ability of EVO to shut itself off properly or restart after normal power supply is restored. All EVO motherboard, RAID controller, and server functions are housed in the base unit.
Keep in mind also, that you may want to power some other devices on the same UPS. For instance, if you have Ethernet switches you may want to keep them on the UPS too, so you can still log in and manage EVO in the event of power outage.
Ideally, ALL devices in a network would have some battery backup — workstations, network switches, and storage (including expansion chassis). That way, even if power were to fail, users could still SAVE their current work before the battery level dips low enough for the UPS to tell EVO to begin a shutdown.
The recommended UPS for 8 bay and 16 bay units is APC Smart-UPS X 2200VA USB & Serial RM 2U 120V.
Refer to the EVO manual for more information and steps to configure EVO to monitor your APC UPS.