Most workstation Linux installs in MCECS are Tier 1 and supported and maintained by the CAT.
The CAT can also maintain a server as a “file server” that only exposes files over an NFS (Unix/Linux) or SAMBA (Windows) interface. New file servers will be loaded with FreeBSD, but some existing servers run Solaris.
Tier 2 Linux loads have the limitation that they do not have access to user’s regular NFS home directories, user data is usually stored locally on the machine or provisions are made for home directories for a small set of users to have homedirs that live in a stash. In addition stashes are not accessible over NFS to Tier 2 loads by default. Access is only granted to stashes if requested by the stash owner.
These machines are completely unsupported by the CAT in their day-to-day operation.