jgreco
Resident Grinch
- Joined
- May 29, 2011
- Messages
- 18,680
Sorry if not clear, I should have not have brought up ecc ram. If the ups is low quality, with all the redundancy in the world, your data won't be safe. I don't know which UPS to buy because "the manufacturer" keeps cutting corners and masking inferior product as same model and price. I have searched and found like 4 brand names people got working. I don't care about brand names but I have to look because I don't want to buy incompatible hardware.
Even a low quality UPS protects against certain types of problems, such as momentary outages. That can be sufficient until the generator backup kicks in.
The problem is that UPS functionality is the big question. "4 brand names people got working" is probably a sideways way to look at it. All UPS's work with FreeNAS - they provide power when the power goes out. It is a question of the finer points. For example, here, we've got a bunch of gear protected by APC SMT's. These have been very pleasant to work with, but they do not work with NUT unless you also happen to have the network management card, so they're probably a nonstarter for home FreeNAS users.
On power loss, the unit has an idea of what its expected runtime is, and will start doing what's called load shedding. It can turn off sets of outlets to help maintain uptime on others, and eventually it will reach a point where it either gets a command from the control host to shut down, or signals the supported hosts that a low battery shutdown is imminent. On restoration of power, the unit will wait until the batteries are sufficiently recharged, and then powers the load back on. Getting all of this right is not total rocket science, but it is functionality that is missing in the lower quality (lower price) units. It is the edge cases in particular that foul up the works, such as, what does the UPS do if it and the hosts have agreed to dump, and then power returns?