Good afternoon,
How much disk space should we allocate a virtual machine to host a full CentOS mirror?
Background:
We're in the process of establishing a new publicly available open source software mirror here at the Pacific Northwest National Laboratory (http://www.pnl.gov). The base system is running Varnish (http://varnish-cache.org/) with 32GB of RAM cache and a 10Gbit/sec network uplink. PNNL has multiple 10Gbit/sec links to ESnet (http://www.es.net/) and the Pacific Northwest GigaPOP (http://www.pnw-gigapop.net/).
For each Linux distribution hosted we're setting up a virtual machine running that distribution. That way we can ensure the distribution's native mirroring and synchronization tools are available.
Internet users will ask the Varnish cache for files, and if a given file isn't in cache then Varnish will pull that file from the back-end virtual machine to serve it to the end user. When a new release hits the street, the most popular CD and DVD ISO images should stay resident in the Varnish RAM cache. We hope this strategy lets us get away with relatively inexpensive / high capacity disk drives while still achieving good network throughput.
I looked through the FAQ and the centos-mirror list archives; if I missed a disk space recommendation please feel free to redirect me and accept my apology for wasting your time.
Thank you and best regards,
Bill Nickless
(for the PNNL Public Software Mirror team)