Recovering Files from Snapshot Backup on Scientific Computing Linux Clusters

Update 06/01/2022: Please be advised that snapshot backups have been discontinued until additional storage becomes available.


Looking for a copy of a file from before it was modified?  Need a file that has been deleted or can't be found?  It happens, fortunately the BriefCASE storage system takes periodic snapshots of its file systems which can be used to retrieve earlier copies of files in scenarios like these.  Note that not all folders on Scientific Computing (SciC) Linux Clusters are on the BriefCASE storage, for those that are not there may be a tape backup available.

Old snapshots are automatically deleted!  Don't delay, if a file needs restoring do this as as soon as possible.

Snapshots are kept (subject to available space) for home folders and folders under /data.  Snapshots are not kept for /scratch

How to identify the snapshot folder location

Snapshots are kept in a special hidden folder ".snapshot" which does not appear in any file listing. Despite not being visible to the "ls" command, if there are snapshots available for any location the command "cd .snapshot" will allow you to enter the snapshot area.

  • change directory "cd" to the location where files need to be restored to
  • change directory to the snapshot area with "cd .snapshot"

How to restore files from snapshot backup

 cd .snapshot

Once here, list the available snapshots which are ordered by date. 

$ ls -1

Each dated snapshot folder contains a read-only copy of the volume at that time.  Browse the snapshots and restore files by copying back to the main folder.

How many snapshots are kept?

The number of snapshots kept varies over time depending on how much data on BriefCASE has changed recently and the amount of free space.  Currently (correct at 12/23/13) snapshots are available from the two previous Sundays and from the previous 4 days.

WARNING: snapshots do not replace the need to keep a backup of your data. It is possible for all snapshots to be automatically deleted if free disk space is low

Reduce the risk of accidental global file deletion

When working at the Linux command line there is no equivalent to the Wastebasket/Recycle Bin on the desktop.   Reduce the risk of accidentally deleting all files by including this code in your .bashrc file.  If for example 'rm test *' were typed when 'rm test*' was intended this function would print a prompt asking if all files in the folder should really be deleted.

alias rm="IFS='^'; set -f; rmstar"
function rmstar
   set +f # re-enable globbing
   local oldargs=$@ # cache command line
   local rm=`which rm 2> /dev/null`
   local skipdel=0
   if [ $# -gt 0 ];
      local rmstarfound=0
      # search for a '*'
      until [ -z "$1" ];
         case "$1" in
            "*") rmstarfound=1; break;;
            *) ;;
      # if a '*' was found prompt for confirmation
      if [ $rmstarfound -eq 1 ]
         ask "$RED Do you really want to delete all files? $NC "
         if [ "$?" -eq 1 ]
   if [ $skipdel -eq 0 ];
      $rm $oldargs
   unset IFS


Go to KB0027944 in the IS Service Desk

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