jblomer

A key difference is that the file system contents is preprocessed into content-addressable storage (somewhat similar to the format in a .git folder). Also a number of features and optimizations to make it work well as a shared software area, which is characterized by many small, often memory-mapped files and a meta-data heavy access pattern.

The data is not part of the images. It's only the software. In the vast majority of cases, any particular data processing job requires only a tiny fraction of the available software. For instance, a few hundred MB out of a few tens of GB for a typical LHC application software release.

The name is a play on the old CERNVM mainframe.

The project started around 2007/2008 and produced a virtual machine image to run LHC experiment applications in the cloud. In order to keep image sizes manageable, we looked into network file systems that could distribute the application software (including AFS/Conda, HTTP-FUSE [1], Igor-FS [2], GROW-FS [3]). None of them ticked all the boxes, so we developed CernVM-FS (CVMFS), which then developed a life beyond CernVM.

[1] https://kernel.org/doc/ols/2006/ols2006v2-pages-387-400.pdf [2] https://indico.cern.ch/event/28823/contributions/658268/atta... [3] https://iopscience.iop.org/article/10.1088/1742-6596/219/6/0...

Project owner here. Most likely yes, pending speakers' consent.