With the combination of LoBoS 3 and Biowulf, there was a need to upgrade the LoBoS 2 cluster which was, by 2001, showing its age. The new cluster was designed with 70 compute nodes. In a departure from previous clusters, these nodes would use AMD CPUs instead of Intel chips. LoBoS 4 also saw the deployment of Myrinet, a proprietary high-bandwidth, low-latency data link layer network technology in the LoBoS cluster.
Unfortunately, these nodes had reliability problems. In particular, the motherboards proved problematic, requiring frequent reboots, which put undue stress on the power supplies, which in turn failed at a much higher than expected rate. In addition there were problems with ensuring sufficient power and cooling for the nodes, although these issues were finally resolved. However, because of the component failures, the LoBoS 4 nodes were returned to their vendor in exchange for a discount on some of the nodes that would eventually become LoBoS 5.
|70 Compute Nodes||
|4 master nodes||
|Myrinet switching hardware||
A Myrinet M3-SW16 line card.