Linux Backups and Restorations

Information on Linux file backups

Reviewed by John Sopko 6/17/2014

This article describes the backup system, retention policy, and schedules and how to request restorations for the department’s local Linux files.

The department’s backup system and software

Computer Services backs up the department’s local UNIX files using the EMC Networker client/server software and a Data Domain deduplication system, which keeps backups on spinning disks.  We back up our critical operating system and application software as well as user purchased disk space.

In addition, Computer Services will provide backups for a /backup partition on department-owned Linux desktop system.  Backup quotas are:  40 GB for faculty and 20 GB for staff and graduate students.  The backups run automatically 7 nights per week. We keep backed-up data (and can restore it) for a period of three months.  This system is voluntary and by request only.  If you would like to have backups done on your Linux system, send email to help@cs.unc.edu.  Please include the name of your office computer in the request. See Linux Desktop backup and restoration details below.

Backups of other filesystems are possible but must be approved by the Department’s IT Director and will be done for a fee, except that all disk space purchased from Computer Services is  automatically backed up.  See the disk space fee help page for information on purchasing Linux disk space.  Please email help@cs.unc.edu if you need assistance with file backups.

Backup schedules and retention policy

User purchased disk space and system files are backed up daily.  The department’s policy is to retain backups for three months.

File restorations

If you need a file restored, it is important to know whether the file is in AFS or not, because you can access the most recent AFS backup online.  For information on how to do this, see AFS file restoration.  If your Linux file is in /afs/cs.unc.edu/…, then it is in AFS file space; otherwise it is in NFS or local file space.

To request to a file restoration, send email to “help@cs.unc.edu”.  Help mail is always read, whereas mail to a given staff member might not be if that person is on vacation or out sick.  In your request please include as much of this information as possible:

  1. The full path name of file or directory you want recovered, e.g., /net/grouse/walk1/data/lost.  This can be obtained by getting as close as possible to the point the file was lost and doing a ‘pwd’.
  2. Computer hostname name on which the file was lost.
  3. Date file was lost.
  4. Date and time of last modification to file, or when the file was created.  (Files created and lost in one day between 8 AM and Midnight are not recoverable as they have never been backed up.)

Linux Desktop backup and restoration details

We have an rsync server named lbackup.cs.unc.edu, (host alias for monkfish.cs.unc.edu).  The system currently has 1TB of space for rsyncing data from Linux desktops.  The general method we use to backup a Linux desktop is to configure a /backup partition and the rsync server daemon on your linux desktop. We run a nightly cron job to rsync your /backup data to the lbackup server. Your data then goes to our tape backup system daily.  You can recover your own deleted files if you copy them before the next nightly rsync backup which runs starting at 10:10pm.  If you need to go back more then one day please send email to help@cs.unc.edu as described above in File restorations.

To see if you can recover you own backup files ssh login to host login.cs.unc.edu, (alias for bluetang.cs.unc.edu):

cd /net/lbackup/data/desktops
ls -l

Your desktop /backup directory is located under the host name of your desktop. There are two empty files named “rsync_started” and “rsync_finished” that have time stamps appended to them so you can see the last time your desktop was rsynced to the lbackup.cs.unc.edu server.

You can use the scp or sftp command to copy files to your desktop.  You can copy files to the local /playpen directory on login.cs.unc.edu if you need to stage files locally.

IMPORTANT: If you maintain your own local linux desktop login accounts you should use your department numeric network login user id, (uid).  For example to query for your numeric uid, ssh to login.cs.unc.edu and execute:

ypmatch login_name passwd

fish:x:1234:1003:Big Fish:/home/fish:/bin/tcsh

where login_name is your Computer Science login. The third field is your login uid, in the example above the login name is fish and the uid is 1234. If you need assistance email help@cs.unc.edu. If we backup your data to the lbackup server and your desktop uid is not the same as your department uid you may not be able to gain access to your files and will need assistance.