NAME

       s3qllock - Make trees on an S3QL file system immutable

SYNOPSIS

          s3qllock [options] <directory>

DESCRIPTION

       S3QL is a file system for online data storage. Before using S3QL, make sure to consult the
       full documentation (rather than just  the  man  pages  which  only  briefly  document  the
       available userspace commands).

       The  s3qllock  command  makes a directory tree in an S3QL file system immutable. Immutable
       trees can no longer be changed in any way  whatsoever.  You  can  not  add  new  files  or
       directories  and you can not change or delete existing files and directories. The only way
       to get rid of an immutable tree is to use the s3qlrm command.

       s3qllock can only be called by the user that mounted the file  system  and  (if  the  file
       system  was  mounted  with  --allow-other  or --allow-root) the root user. This limitation
       might be removed in the future (see issue 155).

RATIONALE

       Immutability is a feature designed for backups. Traditionally, backups have been  made  on
       external  tape  drives.  Once  a  backup  was  made, the tape drive was removed and locked
       somewhere in a shelf. This has the great advantage that the contents of the backup are now
       permanently  fixed.  Nothing (short of physical destruction) can change or delete files in
       the backup.

       In contrast, when backing up into an online storage system  like  S3QL,  all  backups  are
       available every time the file system is mounted.  Nothing prevents a file in an old backup
       from being changed again later on. In the worst case, this may  make  your  entire  backup
       system  worthless.  Imagine  that  your  system gets infected by a nasty virus that simply
       deletes all files it can find -- if the virus is active while the backup  file  system  is
       mounted, the virus will destroy all your old backups as well!

       Even  if  the  possibility of a malicious virus or trojan horse is excluded, being able to
       change a backup after it has been made is generally not a good idea.  A  common  S3QL  use
       case  is to keep the file system mounted at all times and periodically create backups with
       rsync -a. This allows every user to recover her files from a backup without having to call
       the  system  administrator. However, this also allows every user to accidentally change or
       delete files in one of the old backups.

       Making a backup immutable protects you against all these problems.  Unless you  happen  to
       run into a virus that was specifically programmed to attack S3QL file systems, backups can
       be neither deleted nor changed after they have been made immutable.

OPTIONS

       The s3qllock command accepts the following options:

          --debug
                 activate debugging output

          --quiet
                 be really quiet

          --version
                 just print program version and exit

EXIT STATUS

       s3qllock returns exit code 0 if the operation succeeded and 1 if some error occurred.

SEE ALSO

       The S3QL homepage is at http://code.google.com/p/s3ql/.

       The full S3QL documentation should also be installed  somewhere  on  your  system,  common
       locations are /usr/share/doc/s3ql or /usr/local/doc/s3ql.

COPYRIGHT

       2008-2011, Nikolaus Rath