[369] in Info-AFS_Redistribution
Re: acls ...
daemon@ATHENA.MIT.EDU (doeringd@sdsc.edu)
Thu Oct 31 19:15:45 1991
Resent-From: Liz_Hines@transarc.com
Resent-To: Info-AFS@transarc.com
Date: Wed, 30 Oct 91 18:13:25 GMT
From: doeringd@sdsc.edu
To: bb+transarc.afs.psupport.infoafs-errors@transarc.com
X-St-Vmsmail-To: ST%"bb+transarc.afs.psupport.infoafs-errors@transarc.com"
Be wary of tar. Use cpio. The tar command was originated for tape service.
As such, it assumes that you can't expunge an unused file space on a piece
of tape and treats the disk space the same way. That is, once a tar file
contains an object, deletion of that object simply removes it from the tar
index, BUT THE PHYSICAL DISK SPACE IS STILL OCCUPIED BY THE OBJECT: you just
can't get to it anymore. Thus if you keep deleting objects from the tar file,
the tar file gets no smaller. Worst still, if you replace an object in a tar
file, the tar file grows and grows in size: the replaced objects (deleted)
never go away. You must extract all items from the tar file (actually extracts
the deleted items, too, and then overwrites them or deletes them) and then
write a new tar baby. However, cpio does this automatically and thus helps
(forces) you to keep your file space down.
Don Doering
SDSC
San Diego Supercomputer Center
