Ariel Cluster

Our fourth Linux cluster, collectively known as Ariel, consists of 72 dual-processor Xeon systems divided into three 24-node clusters. It was designed in 2004, taking advantage of Sun's matching grant program to let us move towards space-efficient rack-mount systems.

We have photo-chronicled its configuration here.

System Specifications

ariel, puck, portia

Each of these clusters consists of twenty-four dual-processor Intel Xeon systems. Each cluster is controlled as a single root node, which is controlled much like a standard Linux box. Computations are divided up and transferred to the rest of the cluster by a single front end machine. The other machines have no keyboard, mouse, or monitor; they only connect via the network. The machines are connected through three 24-port managed gigabit switches.

In addition to the main clusters we have purchased six additional nodes, configured for serial use but usable as spare nodes if others should fail. These nodes are configured identically to the rest of the systems.


Using the molecular dynamics code NAMD we achieved these speedups on a 92,000 atom system on our clusters (as of June 2004, benchmarked with NAMD 2.5):

CPUs Sec/Step Speed-Up Efficiency
1 3.97 1 100%
2 2.05 1.93 96.6%
4 1.03 3.84 96.0%
8 0.538 7.39 92.4%
16 0.280 14.19 88.7%
32 0.149 26.7 83.3%
48 0.107 37.0 77.0%

Breakdown of Costs (at time of purchase)

Count Unit Cost Total Description
Systems 78 $1,997.50 $155,805.00 SunFire V60x
Racks 3 $3,786.56 $11,359.68 Sun Rack 900-38
Rackmount Equipment 78 $120.00 $9,360.00
Gigabit Switches 3 $1,678 $5,034.00 SMC TigerSwitch 8624T
Cables + Shipping (Approx.) $1,500.00
Total $183,058.68