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WULFFNET Hardware

Hardware Introduction

The WULFFNET Hardware is composed of two server systems and fourteen compute nodes. Since one of the main purposes of the cluster is for x-ray tomography reconstructions, two servers were chosen so that data could be transferred on to the hard disk of one server while the second server orchestrated the computation nodes for the reconstruction. There are several pieces of common hardware to each server.

Disclaimer

None of the hardware listed below should be construed as an endorsement by DND-CAT or any of our member institutions. This is simply what we used for our current cluster.

Pictures

Lets face it, thats what you have come to see. And after all, a picture says a thousand words. So, here are a few of our cluster:

Networking and Communications

Wulffnet currently uses an Allied Telesyn FS716 16 port 10/100 Switch for internal communciations. The consoles of each of the nodes and servers are brought to a single "workstation" point using Power Reach KVM Controllers. The monitor for the system is a Princeton Ultra 72 Monitor.

Server Configuration

Each of the two servers is configured with the following hardware:

In addition, the two servers share a Plasmon D120 CD-R Jukebox which contains four 8x CD-R burners and 120 CD-Rs. The jukebox has two SCSI interfaces each containing two drives. One SCSI interface is dedicated to each server. This jukebox helped solve several data transfer issues for us. Some of our experiments collect tens of gigabytes of data per sample. While we encouraged our experimenters to ftp the data back to their home computers, we quickly realized that data storage at the "home lab" could be a serious bottleneck. We started burning CD's since this was a format that could be read on Linux, Unix, Irix, Macs, PC's etc..., the media cost is relatively low, software was available to control the robot and which could be easily folded into excellent multivolume CD-R backup software for Linux. The backup software uses mkisofs and cdrecord to make ISO9660 file systems. We mount the CD and use star to verify the CD (cd /mnt/cdrom; star -cPM . > /dev/null). This combination of software and hardware solved the transport, storage, and compatability problems. We did consider initially using tapes for this purpose, but we found that we could not rely on a particular tape drive being available at the "home lab". CD's however, are everywhere.

In addition to the Plasmon Jukebox, we also have a Primera Signature III CD Color Printer with their Conductor Autoloader so we can print designs and information directly on to the CD.

Currently, Redhat is our distribution of choice.

Node Configurations

The original Wulffnet consisted of 8 Dual Processor 450 MHz Pentium III machines. Later we added 8 800 MhZ Athlon systems. Recently we have replaced the Pentium III machines with 1.2 GHz Athlon systems and are now turning the P III systems into desktops systems. The current node configuration for Nodes 1-8 are: and Nodes 9-14 contain:
John Quintana (jpq@northwestern.edu) / May 2001