I'm upgrading our cabinet at our colocation for A/B power and wanted input on which of our options are good or bad.
First, a bit of an overview of our setup: We currently have a single circuit feed into our cabinet. We have a few servers that are mission critical with dual power supplies and all the other mission critical servers are upgradable to dual power supplies. Our options as I see it are this:
- Wire the servers with dual supplies to A/B power and then divide the other servers evenly across A/B sources.
- Get an extra power supply for all mission critical servers and wire all servers to A/B power. (with the exception of our firewall and switches which cannot accommodate dual power - those would require manually plugging into the B source if A went down.)
- Get a PDU that automatically switches to B power when A goes down (like here: http://www.tripplite.com/en/products/model.cfm?txtModelID=4809)
To me #3 sounds like the best option since we could just plug in our servers to that PDU and if A goes down it will automatically switch to B. The main possible drawback is that it does contain an ATS which could potentially fail and then we'd be in serious trouble. For #3 to work we'd need to know that a unit like in the link above was reliable. Otherwise we'd opt for #1 or #2.
I'd be interested it hear your thoughts on if #3 is a good approach to increase our power redundancy or if we should take another route.