The information below will be helpful in getting a new user started in our Linux environment.


For your account on our cluster, the following information is relevant.

The Initial password will be sent in a separate message. You can change your password once you've logged in by using the "kpasswd" command.

It will take up to one hour after it is changed before the new password will take effect. (This can only be done from one of the login machines below).

We have 7, essentially equivalent, login machines that you can use ssh client , such as putty, to connect to:
  • umt3int01.aglt2.org
  • umt3int02.aglt2.org
  • umt3int03.aglt2.org
  • umt3int04.aglt2.org
  • umt3int05.aglt2.org
  • gc-7-31.aglt2.org
  • gc-9-36.aglt2.org
and the last 2 nodes (gc-x.aglt2.org) are also gpu nodes from which you can run GPU jobs.

You can either use the login nodes to run interactive jobs and access your files, or submit jobs to the backend HTCondor system from these login nodes.

For information to submit or debug your Condor jobs, please refer here :

Your home account is in afs space, and your home directory is /afs/atlas.umich.edu/home/your_username, has 1GB of storage, and is backed up. A backup from the previous day is saved as /afs/atlas.umich.edu/home/your_username/backup, and it is not counted against your storage quota for AFS. You can use this backup directory to recover files from the previous day if they are lost.

For work requiring more space, there is a directory area in NFS at /atlas/data19/your_username which is owned by you. Your disk quota there is 100GB.

For most people, additonal storage space in lustre is also created under /lustre/umt3/user/your_username Which has unlimited space shared with all UM Tier3 users.

And if you do not see /lustre/umt3/user/your_username , and need the extra space, please contact us to create this space.

All the storage spaces are accessible from all the login nodes and work nodes.

Please note: Neither the NFS nor the Lustre space has back up!! It is user's own responsibility to make backup for important data which are stored in either the NFS or the Lustre file systems.


Be aware! When working on an office workstation, files placed on your desktop are counted towards your afs quota, and it can be very easily filled this way. Please use the NFS directories for the bulk of such storage.

If you wish to use (non-backed-up) local storage on your office desktop, please let me know and I will prepare a location for you.

Since your home directory is in afs, you will need to provide an extra layer of security for your ssh keys, should you choose to store them for ease of access within our systems. You can look at the URL below for information on how to do this. The .private directory referenced in this document is already created with the correct permissions, so all you'll need to do is place your keys there for safe keeping.

https://www.aglt2.org/wiki/bin/view/AGLT2/SetupSSHKeys


Note that your password tokens expire after 30 days if you log in to an interactive machine via ssh key, but if you log in via password, they are immediately refreshed. Tokens can be renewed at any time by

kinit
<enter your password>
aklog

Then you can run

tokens

to check the validity of your AFS tokens.



A recent security change in our afs directories means that most of your afs directory can be LISTED by other users, but no file can be READ by other users to see the content. We have provided two directories for you to work within this limitation.
~/private cannot even be listed by any other user.
~/public can be used to share files with any other user as they have the required READ permission. A 3rd such directory, ~/.private (note the dot) is protected such that not even system administrators can see the content.


-- WenjingWu - 10 Jul 2025
Topic revision: r3 - 29 Sep 2025, WenjingWu
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