Have you ever had to set up a UPS for a midsize server room? Heck, have you ever had to install a UPS into even your average server cabinet? It isn’t exactly a walk in the park. As for buying one, well you might sit with a small situation if you don’t assess your needs correctly from the start. Here are six easy to follow steps to guide you through it all.
1. Where does this one go?
It is kind of obvious, but it is vital to ensure that you have enough sockets available at the back of your UPS to meet your requirements. The number of available sockets decreases pretty quickly after you cover your Internet-access equipment such as routers, modems, firewalls, and VPN hardware. Double that if you are running a multi-homed configuration, or have servers equipped with redundant power supply units. What else? Mmm… Oh yes, monitors and KVMs should have a protected power outlet, too. (Just power them off when not in use) Another solution might be to buy standard power strips and manually rewire their default connectors with plugs that can fit those on your UPS. This is useful for protecting multiple minor pieces of equipment, such as modems and other low-drain equipment.
Some mid-range UPS models offer the ability to daisy-chain additional battery packs from the main UPS. The additional battery packs are usually rack-mountable as well and represent a convenient way to increase the backup supply time of your UPS beyond the default configuration.
An advantage of going this route is that you get to share your available battery runtime more efficiently across all of your equipment. Other potential benefits, the cost may be lower when compared to scaling up to a higher range of UPS, as well as the possibility of hot-replacements of batteries.
On the flip-side of the coin, you have to consider that certain mid-range UPS models do offer a number of features such as the ability to stagger power-on times, as well as giving you the ability to remotely power-cycle equipment at the power receptacle level. Having two separate UPS units working at 40% load does represent a full backup complement.
3. Beware the deep end
Let’s talk rack-mounted equipment for a moment. You will do well to ensure that your UPS has sufficient space towards the rear portion after mounting it onto your rack. While a 19-inch UPS will fit quite snug into a 19-inch rack, the fact is that not all 19-inch racks are built the same.
Smaller racks built to a reduced footprint or second-rate racks might not have enough spare breathing space for you to plug in the power connectors and still be able to close the back door. Can anyone say ‘Thanks allot, Geniuses”?
In addition, it is also worth noting that higher-end UPSs usually use customized or non-standard plugs on the UPS-end of the rope. It will be sensible not to position your rack too far away from the wall power socket.
4. Power for the nations
It is normally best to create a separate branch circuit from your building’s main power switchboard. This will help reduce instances of your team of pink monkeys tripping your server room’s power by plugging in a faulty microwave oven.
5. Configure the shutdown of servers
Many people forget that UPSs are meant only as a backup measure for power outages – this means it is not an uncapped source. In an extended blackout or brownout, you do need to shut down your servers to prevent data loss. The easiest way to get this done is to install the software provided along with the UPS. This will generally monitor your UPS via a USB or Serial cable and start shut down sequences in the event of an outage. Most of this software will allow you to have certain scripts run once the sequence is started, this can be used to shutdown other servers that are not connected to some sort of monitoring system. And please, I beg of you, test-test-test-test-test!! Just test these shutdown sequences! It’s all good and well having systems in place; however, you don’t want your test run to be an unexpected one.
6. Closing Points
Do not assume all the connectors on a UPS are identical. Watch out for UPSs with power outlets that are divided into “Battery backup” and “Surge suppression”, making sure to plug your equipment into the correct outlet.
Determine whether you need an off-line, line-interactive or double-conversion UPS. Basically, it makes sense to go for a double-conversion UPS if budget allows. Due to the presence of a rectifier directly driving the inverter, a sort of electrical “firewall” is formed to better protect against noisy or poor power environment. An off-line UPS will only kick in during a power outage, and a line-interactive lies somewhere in between.