In order to better interoperate with standard Linux operating systems, UTCS is remapping some of our unix groups to new group identification numbers (gids) as well as retiring some legacy groups.  Because files are associated to groups via gid numbers, any file tied to a group that needs to be remapped will also need to have its group identifier updated, either temporarily or permanently.  While many of the files that need updating are system files that we maintain, there will be cases where such files belong to individuals. In these cases, we ask that you change the groups yourself within 7 days or allow us to do so for you.

Why are groups being remapped?

Due to our long history with unix, we have legacy groups, as well as low-numbered legacy gids. These groups and gids collide with current standards, severely complicating deployment of new Linux OS versions. A significant amount of staff time goes into modifying the default Linux OS to fit in our environment, both at the time of initial deployment and on an ongoing basis. Deployment of new OS versions to CS systems trails initial release by at least six months, and sometimes longer. Existing deployments cannot be upgraded by normal procedures, meaning older OS versions continue to be used after their standard (and sometimes extended) End Of Life, with concomittant support requirements.

How are you identifying files that need their groups changed?

We plan to use several tools to identify files that belong to groups that require remapping. For files residing on our NetApp Filers, we will primarily use NetApp's XCP File Analytics utility, which provides fast, efficient indexing of NFS volumes and powerful querying of those indexes that allow us to identify files whose groups will need to be changed. For files that reside on local disks or for searching small subsets of files on the filer, we will utilize the unix "find" utility (or the rust variant "fd"), which can perform a real-time search for files belonging to specified groups.

What groups will be re-mapped?

Since this will be an incremental process, we don't have a complete list, but groups with gids below 1000 (and particularly below 100) are most likely.  Additionally, they fall into two basic types:

• Primary groups - These are groups most likely to be a user's primary group, such as prof, grad, or under.  By default, user files are assigned these groups when they are created.  Files in these groups will be addressed in a later phase of this project.
• Secondary groups - These are usually groups with few, if any, members. In general, files would have to be purposely set to these groups, so they occur less frequently.  The initial phase of the project primarily focuses on files in secondary groups.

Who does this effect?

Eventually, nearly everyone, but in the initial phase, the longer you've had a UTCS account, the more likely it is that you have files in legacy groups.  This means faculty and staff are more likely to have such files, but graduate students may also be affected.  Our initial communication will target these groups.

How will I be notified if files I own need their groups changed?

In the initial phase of the project, we'll send you an email with a list of files, the group they belong to, and the group they should belong to instead.  We'll also specify a date by which we ask that you change the listed files, and after which we will make the changes for you.

How do I change the group of a file?

The simplest way is to use 'chgrp' from the linux command line, in the form 'chgrp {groupname} {filename}' (You can provide more than one filename if you are changing all of them to the same group).  If you need to change the group on a symbolic link, you will need to use the '-h' option to prevent it from instead changing the file the symbolic link points to.

Can you just take care of changing the group for me?

Yes.  For the initial phase of the project, if you'd prefer we just make these changes, we'll provide a link to a Qualtrics form in the notification emails we send out where you can ask us to make changes on your behalf.

Can I just delete the files or do I really need to change the group?

Absolutely. Especially in the initial phase, the files in question may be quite old (from when we still supported Sun systems), so if you no longer need them, feel free to delete them instead.