- Ultra-low power means less need for cooling
- High-density 2U chassis
- Hot-swap server nodes
- Dual Gigabit interfaces per node
- 24 hot-swap direct attached disks
- IPMI remote monitoring and management
- Limit of 4GB of 800MHz RAM per node
- Servers can only be hot-swapped in pairs
- Performance lags behind Intel Xeon and AMD Opteron alternatives
If you think about Intel's Atom processor at all, it's probably as the low-power CPU inside netbooks and tablets. So to dicover no fewer than eight inside a rack-mount chassis could come as something of a surprise. But that's exactly what you get in the Green Power 2200-T from Boston Limited. This is a high-density server platform designed to host applications where low power consumption is more important than processing ability.
One way of looking at the GP 2200-T is as a kind of low-end blade server, delivered in a compact and very well engineered 2U rack-mount chassis. OK it's not quite a blade server, but it's pretty close, with AC power delivered to the chassis as whole by a redundant pair of 80 Plus Gold Level supplies. These slide in at the back with, arranged on either side, four processor trays in which are mounted SuperMicro motherboards housing those all-important Intel Atom processors.
The Green Power 2200-T has dual redundant power supplies and four motherboards each with two dual-core Atom D525 processors
To be precise, each board is equipped with a pair of dual-core Intel Atom D525 processors, but not in a conventional dual-socket SMP layout. Instead, the motherboard effectively delivers two separate and wholly self-contained servers, each with its own processor accompanied by up to 4GB of (non-ECC) DDR3 memory.
With the CPUs clocked at just 1.8GHz and the RAM running at only 800MHz, by server standards it's a pretty conservative specification. However, it comes with an absolutely tiny power and cooling envelope — especially when compared to a more conventional Intel Xeon or AMD Opteron setup. Indeed the TDP for the Atom is just 13 watts, and even with all eight processors running it will only consume a bit more power and generate a little more heat than a conventional single-socket server.
Network attachment is via Gigabit Ethernet interfaces — two per server node — with sockets terminated at the rear of the tray. You can't add any plug-in cards, but there's a connector for a local monitor plus a pair of local USB ports per node. These are unlikely to be used, as IPMI management support is built in; a neat Java-based management utility is bundled with the server to support remote monitoring and graphical remote control, compete with virtual device mapping —right down to the BIOS level.
Setup for testing was remarkably easy, not least because Boston builds each server to order and delivers it ready-configured with your OS of choice. Our review system shiped with trial versions of Windows Server 2008 R2 Foundation installed, one per node, so there was very little to do other than fit it into the rack and hit the power button.
Should maintenance be required, the server trays slide easily in and out from the back of the chassis and are hot-pluggable, the only limitation being that, with two server nodes in each, you effectively disconnect both whenever a tray is removed. The cooling fans aren't quite hot-pluggable but, thanks to the low power requirements, aren't really stressed and so shouldn't need replacing that often. They're also remarkably quiet in operation.
A passive backplane distributes the power and also connects the server nodes to the local storage, which comes in the form of up to twenty-four hot-pluggable 2.5in. disks arrayed across the front of the unit. Each node can be directly connected to three of these via a dedicated Intel SATA controller on the host motherboard; the review system had 16 500GB Seagate SATA drives configured as mirrored pairs.
As it's built to order, other disk capacities can be specified or SSD storage fitted — although that would be very expensive and wouldn't deliver much in the way of value. Indeed, according to Boston, customers are more likely to connect to external storage using iSCSI than go for direct-attach SSD on this platform.
So who's buying the GP 2200-T, and what can it be used for?
When it launched, service providers were seen as one of this server's main target markets. That's since been expanded to encompass any business looking to reduce the total cost of server ownership. Starting at just £699 (ex. VAT) per server node, it's certainly an affordable buy; and with each server drawing just over 30W even under load, the GP 2200-T is remarkably cheap to run.
It does lack performance, though, so it's not the sort of platform that will appeal to HPC buyers, no matter what the TDP rating. Neither is it any good at virtualisation. However, the Atoms aren't as slow as you might expect, and with sixteen cores to play with over eight servers, the GP 2200-T makes an ideal platform for applications such as search engines that can exploit distributed processing power.
Add a load balancer and you've got a mini server farm, so the Green Power system will also meet the requirements of a lot of web applications. It could also be used to host file sharing, email and Blackberry servers in small to medium-sized companies. However, the cost of licensing Windows across all eight nodes needs to be considered, and the majority of deployments of this type are likely to run Linux.
Available through a network of resellers, the Green Power 2200-T is a unique and interesting solution. We did have to mark it down a little on performance, but it more than makes up for that with its low power consumption and undemanding cooling requirements. If power isn't an issue, Boston uses the same hot-swap chassis to host Intel Xeon- and AMD Opteron-powered servers in its Quattro range.