Four CPUs aren’t always greater than two

Yeah, it’s got a Hemi. Four of them, in fact.

Appro recently unveiled its 1U, quad-Opteron, 848-based 1142H server and I put it through its paces. The short story is this server moves like a much larger system. Although the server is packed with performance power, its limitations will likely relegate it to a fairly narrow audience.

In theory, 1U servers are destined for medium-duty tasks. They make good directory servers, DNS/DHCP servers, application and Web servers, but rarely do they move beyond those tasks. Internal expansion, or lack thereof, is usually the primary reason.

Add a few SAN HBAs into the mix, however, and a standard 1U, dual-CPU server can really stretch its legs. Even with two additional processors in the chassis, the Appro 1142H lacks relevance for many organizations, due to the server’s limited expansion possibilities.

Appro doesn’t target standard enterprise tasks with the 1142H; it looks straight at the HPC (high-performance computing) and clustering infrastructures. Given a standard 72-inch rack, and discounting potential network and power units, 42 rack units are available. Packed with standard 1U servers, this produces 84 processors and 672GB of RAM, assuming 16GB RAM limits on the servers. Naturally, that same rack populated with Appro 1142H servers doubles those figures. That’s 168 CPUs and 1.3TB of RAM. Substantial.

Too Hot to Handle?

Armed with four AMD Opteron 848 CPUs and a maximum of 32GB DDR400 RAM, the 1142H was designed for heavy workloads in tight quarters. Appro shipped the 1142H with RedHat Advanced Server 3.0 preinstalled, but I had no problems reinstalling that OS, nor did an installation of Suse Enterprise Server 9 create any difficulties.

Aesthetically the 1142H is nothing to write home about. The status lights on the front are easily identified, although Appro uses a piercing blue LED for the power indicator and a muted orange light for the unit ID indicator, the direct opposite of what you might expect.

I found the two-piece cover rather difficult to open and secured with rear thumbscrews, preventing easy access from the front of the rack. In fact, I had to exert significant force to open the front of the case. When finally open, however, the mainboard layout is simple and easy to work with.

The cooling system in the 1142H shows some necessary differences from standard 1U servers. There are only six fans present: three small fans in the front pushing air over the sole power supply, and three large side-pull fans mounted directly behind the drive bays.

The big fans pull air from the underside of the case and push air across the two closest processors, with one directed toward the rest of the mainboard. Pulling fresh air from underneath a server isn’t the best idea, but the sheer size of the Tyan S4882 mainboard in the 1142H is probably responsible.

The heat sinks on the CPUs are very low-profile, and come in pairs. Two sets of heat sinks cover the four Opteron 848 CPUs, each set joined by heat pipes to help direct heat away from the processor. Otherwise, there are few baffles inside the case to shape airflow. During my testing, I did note that there was some discoloration of the heat sinks.

I ran tests with the 1142H closely packed between several servers, and drove the system into the red line with continuous MD5 sum calculations for 24 hours. I did not notice any problem with the server’s performance; the 1142H definitely drives like a 4U Opteron system, with plenty of torque and the ability to address large amounts of RAM.

That said, the server did manage to raise the temperature in the lab slightly, all by itself. If the 1142H was sitting near the top of a rack full of servers, it would likely get very warm, which generally leads to a shorter operating life. I didn’t see any overt temperature-related system issues in my tests, however.

Fast, but Limited

Available with either an LSI U320 SCSI controller or an SATA controller, the 1142H can handle two disks within the chassis, but does not support hardware RAID. For most tasks that face a four-CPU system, access to data is critical, and so is performance.

Unfortunately, if you want to add hardware RAID support, it must come in the form of an expansion card, which will take up the only available slot. Otherwise, software RAID is possible but will use CPU resources to function.

In the HPC world, the single available PCI slot can handle a Myrinet or Infiniband card if the on-board Gigabit Ethernet controllers aren’t acceptable. For other data-crunching purposes, however, the 1142H is definitely limited by the one PCI slot and the lack of redundant power supplies.

Connectivity to a Fibre Channel SAN is possible but redundant connections are not. Thus, the 1142H isn’t suited to perform as a high-power, stand-alone system.

All this paints the 1142H into the HPC and clustering corner. That’s a lucrative spot, but it also raises the possibility of using blade servers rather than 1U systems. Blade servers won’t have four CPUs, of course, but rack density will compare favorably against 1U servers.

Thus, the justification for the 1142H is specialized tasks that can significantly benefit from parallel tasks run within a cluster node. The lack of redundancy doesn’t matter as much in this environment, as the loss of a single node would be unfortunate but doesn’t represent the failure of specific services.

Appro considers its 4U quad-Opteron system to be the solution for those specialized applications. Given the relatively low price and footprint, the 1142H might make a reasonable lab or QA server, but I wouldn’t place it in a mission-critical, stand-alone position.

The 1142H also lacks management capabilities of any kind, though Appro offers management tools with its blade servers and some of its other server offerings. The company does plan to implement its system management solution on the 1142H, providing remote administration, health monitoring, and alerting.

All in all, four CPUs in a 1U chassis is a very intriguing notion, but like fine wine and ultra-high-end sports cars, they have a very select audience. If that audience is paying attention, then the 1142H will do well.