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User Notes

This is a brief list of rules for the usage of the physics.uj.ac.za server. Some of these policies may be enforced strictly, others are just suggestions.

Please note that the rules about mail usage derive from discussions with the UJ IT Division; as such, they cannot be unilaterally changed by the system administrators. The other rules are guidelines, based on previous experience and on foreseen usage of this server, and are still open to comments and discussion.

Passwords

  • Change your password regularly - at least once a year.
  • Always choose good passwords:
    • at least 8 character long,
    • mix lowercase, uppercase, numbers and other characters (punctuation and special characters),
    • do not use dictionary words, plain or with trivial phonetic substitutions (like 3 for three or tree)
    • but don't make it so complicated that you need to write it on a post-it under the keyboard
    • Use apg -MCSN for suggestions of good, random but still "pronounceable" passwords.
      Just run it again to obtain another set of choices.
  • Use smbpasswd to change your SMB password, if you use Windows file shares
  • Use passwd to change your Unix shell and mail password
  • Do not keep ssh keys (.ssh/id_dsa) without a password on the server.
    Instead, please learn to use ssh-agent.
  • If you forget your password, it can not be retrieved; an administrator will instead assign you a new one, which you should change immediately
  • The system will run a password testing code to identify weak user passwords.

Mail

The physics server is not meant to be a full mail server:

  • an account there will not correspond to an e-mail address @physics.uj.ac.za.
    • you can only receive mail there as a forward from an official UJ e-mail account (@uj.ac.za or @students.uj.ac.za)
    • you can not use it for sending mail from a mail client (SMTP) - neither from inside UJ nor from outside.
      If you are travelling, please use GMail for sending mail - see this page
  • Only users who request it, and are added to the users_imap group, will have a mailbox.
    • Staff and postgraduate students will be allowed.
  • Other users may specify another address to which system mail (like batch jobs notifications, or disk quota warnings) is to be delivered.

Please note that at the moment (10-Dec-2008) the relaying of mail to the system is awaiting approval from the IT division, and the system can only be used for mail storage

Disk space

Disk space is limited, and must be used with consideration. If your colleagues find that they have no space for their data analysis, and you are occupying disk space with MP3s, they will not be happy.

  • Use your home directory only for your personal, most valuable and irreplaceable data - documents, source code etc.
  • Use the /SHARED area for precious data you have to share with colleagues.
  • Use the /SCRATCH area for data that can be reproduced - files downloaded from a public web server, or experimental data of which you have backup copies on CD/DVD.
  • If you are on a Linux workstation, use the LOCAL area (which sits on the hard disk of the specific PC) for large data that can be reproduced, and to which you need fast access.
  • The MAILBOX space is large, but not infinite. For storage of non-critical or non-work mail, like very busy mailing lists and similar, please use another mail service (for example GMail) instead of the physics server.
    • You can access your mail storage under /MAILDIR/username/Maildir The
  • If the system administrator warns you about an excessive disk occupation, consider that it's because other people may need that space; if you do not address the query, he may have to resort to unilaterally removing your data from the server.
  • As a general rule, the system administrators will do their best to insure the safety of the data stored on the server, but it is ultimately up to the user to insure that their most important data is safe.

As of 10 December 2008, the data on the server is not backed up to external media; until some form of backup is arranged, please make sure that you have your own safeguards in place

Batch jobs

  • Please don't use the group server for heavy, CPU-intensive jobs. It will make you very unpopular with the other users.
  • Instead, submit the jobs to the batch queue of the cluster - it really isn't that difficult.

As of March 2009 - Since there are still few users of this server, it's still acceptable to run CPU-intensive jobs on physfs for short periods of time

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Page last modified on March 26, 2009, at 07:44 pm