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Chapter 7: The AFS File System

7.11 Frequently Asked Questions

7.11.1 Lost Access to Files

Why can't I access files I'm supposed to be able to edit?

First see what permissions you have by checking:

Remember that authentication lasts only a set period of time (6 days in /afs/fnal.gov). If your authentication has expired, you will not have access to your files. You can reauthenticate by running pagsh and klog (see notes in section 7.3.1). Also we encourage you to use telnet in (which always authenticates to AFS) instead of using rlogin. See section 7.3.4 and chapter 13 for information on these utilities.

7.11.2 AFS and the UNIX Command "find"

Why shouldn't I use "find" in AFS space?

You should be very careful about using any command that traverses the file system on a machine that has /afs mounted. Be aware that a find on your system starting at root (/) will traverse the whole AFS file tree, including all the other AFS sites mounted on our cell. This is particularly problematic on some workstations, like Solaris 1 Suns, which by default run a nightly cron job that traverses the whole file system. Also note that the -mount and -xdev options (e.g., find / -mount ... -print) won't recognize an /afs file system boundary; find can't tell the difference between local files and AFS files. The find command is discussed in section 6.4.1.

7.11.3 Error Messages

What does it mean if I get an error message like this:

afs: Waiting for busy volume 536870945 in cell fnal.gov

This is an error message from AFS that indicates that you are trying to access a volume that is busy. There may be a number of perfectly normal reasons for this. It probably means either that your volume is in the process of being cloned for a nightly backup, or that one of the system administrators is in the process of moving your volume to a different disk because the one you are on is filling up. Normally the process that generated the error will just hang harmlessly for a few minutes until whatever locked the volume is finished. If this goes on for more than 20 minutes or so, contact the helpdesk and inquire about what is going on.

7.11.4 Retrieving Old Files

What if I need to retrieve yesterday's copy of a file?

Daily backups of the entire Fermilab cell are available from /afs/fnal.gov/files/backup/. For example if your home area is /afs/fnal.gov/files/home/room3/joe, you should be able to find yesterday's files in /afs/fnal.gov/files/backup/home/room3/joe. The backups are done at 12:45 a.m. seven days a week.

[Missing image]Not all of the volumes are readily available (as of November 1997), but work on that is proceeding. In the interim, if you cannot locate your files, contact the helpdesk to request that your backup volume be mounted so that you can access it.

7.11.5 Link Failure

Why did my link fail?

Hard links can be used only within an AFS volume, not across volumes. Generally, you should use symbolic links. Links are discussed in section 6.3.5.


UNIX at Fermilab - 10 Apr 1998

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