Unix Undelete ?

Luc Chouinard chouinar at centrcn.umontreal.ca
Fri Nov 9 10:13:20 AEST 1990


AFS distributed file system could be an answer.
The AFS file system developped by the Trantor corporation
is really user-friendly from an administrators point of
view.

AFS volumes (filesets):

The volume or fileset unit in the AFS file system comprises
a collection of files and directories, and forms a connected subtree.
Those volumes can be glued together at mount points to make up the
AFS tree.

They can be viewed as standard UNIX file systems on one disk
partition (or multiple partitions on IRIX).

-  Like IRIX 3.3.1 logical volumes, they can grow. But they can
   also shrink and they do it dynamically in respect to a 
   per volume quota.

-  They can be moved from partition to partition and from
   server to server without the users being aware of the move.

-  And (To answer the original question) they can be be cloned.

  When a volume is cloned a backup volume is created which 
  exists alonside of the original read-write volume on the 
  same partition.

  At creation time the backup volume takes practocally no
  space. It will grow when aver a file is modified or deleted
  because a copy of the file will now be effectively part of the
  bakcup volume. Normally backup volumes are mounted on a mount
  point at the top of the original volume (typically .OLD).

  Usually backups volumes are cloned in the morning so users
  can undeleted files all day long with a simple command that
  looks in the .OLD subtree and moves the file from the backup
  to the original volume.

(excuse my english...)
+---------------------------------------------------------+
| Luc Chouinard                   Services Informatiques  |
| Administrateur de systeme       Universite de Montreal  |
+---------------------------------------------------------+
| email : chouinard at CENTRCN.UMontreal.CA                  |
+---------------------------------------------------------+



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