UW Technology Information Cluster

Instead of being one system, the UW Technology Information Cluster is a group of closely-interrelated systems which combine to provide both WWW and FTP service to the UW community and the world. Below is a diagram of the cluster's layout. WWW Cluster Diagram

Hosts and Cluster Philosophy

The hosts represented in the diagram fall into three categories:

Compute Clusters: Clusters of hosts on which developers login.
Information Servers: Hosts which contain the master copy of all exported information and are capable of doing pre- and post-processing of that information.
WWW and FTP Servers: Hosts which actually serve the information to the world.

Note that the WWW and FTP servers each have local copies of the data they serve to the world. This improves the reliability of the servers by making them not depend on other hosts for information. This approach also is capable of scaling to a much greater degree than if one central NFS server containing all data were used. It also allows the WWW and FTP servers to be pure servers with no user accounts or files, which improves both performance and security.

Because data on each of the WWW and FTP servers is local, apush mechanism is used to keep those files in sync with those on the Information Server. wwwpush and ftppush use rdist as the update mechanism, with wrapper scripts to provide locking so multiple developers can push files at the same time.

Compute Clusters

bank.u, red.cac, and shiva.cac are compute clusters which support WWW and FTP developers.

Developers access the information via NFS mounts.

Information Servers

info.cac is the host which holds the master copy of all WWW and FTP information which is distributed to the world. Developers change the information from the compute clusters over NFS. After the information is ready to become visible, it is pushed to the appropriate servers with either the wwwpush or ftppush commands. This host is an Alpha 600au Personal Workstation with 1gb of memory and 40gb of disk.

infox.cac is available for pre-processing data before it becomes available on the WWW and FTP servers (such as the live Red Square image on the UW Home Page). It is an Alpha 600au Personal Workstation with 1gb of memory and 19gb of disk.

WWW and FTP Servers

www.washington.edu and ftp.cac are actually not individual hosts, but are each a cluster of hosts which are configured identically and contain the same information. Multiple hosts are used for redundancy (if one goes down, the other is still up) and scalability (since the hosts are exactly alike, it's easy to add more as needs grow).

The www.washington.edu hosts are Alpha 600au systems with 1GB of memory and 44GB of disk.

The ftp.cac hosts are Linux systems.

wwwdev.cac provides a preview function so developers can view what their files will look like when after are pushed to the production servers. It also provides development and evaluation WWW environments so new information can be developed separate from the production servers.