Student File Server

Rationale

The space available in a system's /home directory is small. Space often runs out, requiring users to frantically decide what to keep, what to delete, and what to move to /scratch or /data.

Prior to 2017, one source of disk-space problems were the files left over from summer students. We're reluctant to delete them (because their work may be relevant in the future), but they were using up disk space in a /home partition that was needed for active research.

The "student" file server milne is a partial solution to that issue. It's the "100-acre wood" where files can be moved, stored, and possibly lost, but not deleted (at least not for several years).

Whom it's for

• Summer students, especially the ones in the REU program.
• High-school students and anyone else doing instructional work.
• Guest accounts created for non-Nevis researchers to access Nevis files, but who aren't going to perform active research on Nevis systems.
• Account archival, e.g., for those who no longer work at Nevis and whose research is no longer of active interest.

If people move in or out of these categories, their files can be moved to an appropriate server. For example, if a former Nevis REU student becomes a grad student here, their home directory on milne will be moved to their research group's login server (kolya, houston, tehanu, shang).

How milne is different

Storage limits

Disk quotas have been enabled on milne. Those with home directories on milne will get warnings when they use more than 9.5GB, and cannot use more than 10GB on the server. This is to get students used to the discipline of storing only critical files in their home directory, and putting re-creatable files in a /data partition.

The home directories on milne are kept in a separate 5TB /files partition. With the 10GB disk quota, this implies we have space for about 500 student or archived accounts before we have to worry about expanding milne or considering alternative solutions.

Backup

The files on milne are backed up nightly to a different server, notebook. However, this backup does not have the multiple layers of recovery of our standard backup. In fact, the reason why the main storage partition is /files is to keep our standard procedure from duplicating it, since the standard backup duplicates all /home directories on all systems.

This means if a student accidentally deletes a file and waits more than 24 hours to tell WilliamSeligman about it, there's nothing that can be done.

Transition

In Jan-2017, the different research groups were asked to look at the /home partitions on their servers and identify those directories that could be moved to milne.

After that, directories will be transferred to and from milne as needed; for example, if a student graduates and leaves academic research, and their work is no longer relevant, their home directory can be transferred to milne.

Why "milne"?

Most of the desktop systems in the REU office (room 118 in the Nevis research building) were named after characters in A. A. Milne's Winnie-the-Pooh: winnie, piglet, eeyore, etc. It makes sense for the "boss" REU server to be named after the "clients'" creator.

Also, milne was formally announced on 18-Jan-2017, A. A. Milne's birthday.

Notes

This is not a permanent solution. If more space becomes available on login servers' /home directories, it's likely that it will be used up by active researchers. Also, we may reach the limit of disk space on milne more quickly that we anticipate, especially if we archive many students' directories that use more than 10GB. This server only delays the decision of when to delete files, it does not eliminate it.