Solaris backup and restore utilities

This article provides an overview of the native backup and restore utilities available within the Solaris operating system.

Overview of utilities

  • Backup Utilities
    • /usr/lib/fs/ufs/ufsdump (linked to /usr/sbin/ufsdump)
    • /usr/sbin/tar
    • /bin/cpio
    • /bin/dd
  • Restore Utilities
    • /usr/lib/fs/ufs/ufsrestore (linked to /usr/sbin/ufsrestore)
    • /usr/sbin/tar
    • /bin/cpio
    • /bin/dd
  • Tape Utility
    • /bin/mt

Utility Summary

  • ufsdump
    • performs backups of ufs filesystems
    • performs backups of specified files
    • able to span multiple tapes
    • does not cross file systems
    • able to perform backups to remove devices
  • ufsrestore
    • able to restore interactively
    • able to restore from remote devices
  • tar
    • able to cross filesystems
    • Can perform remote dumps and restores with compound commands
    • no interactive mode
    • does not support multiple tapes
    • able to restore singular files
    • able to update dump files.
  • cpio
    • able to cross filesystems
    • supports multiple tapes
  • dd
    • very simple dump of file/device to another file/device
    • does not support multiple tapes
    • does not cross filesystems

Basic usage

  • ufsdump
    • this example performs a full backup of c0t0d0s0 and updates the /etc/dumpdates file.
      # ufsdump 0uf /dev/rmt/0cn /dev/rdsk/c0t0d0s0
    • this example performs an incremental backup and updates /etc/dumpdates
      # ufsdump 5uf /dev/rmt/0cn /dev/rdsk/c0t0d0s0
    • thisexampleperformsafulldumptoaremotedevice
      # ufsdump 0uf hostb:/dev/rmt/0cn /dev/rdsk/c0t0d0s0
      special notes: the remote system must have entries for the local host in the root's .rhosts file if dumping to a remote file, the remote file must already exist.
  • ufsrestore
    • this example restores to the current directory
      # ufsrestore xf /dev/rmt/0
    • thisexamplewillstartufsrestore in interactive mode and restore to the current directory
      # ufsrestore if /dev/rmt/0
    • thisexampleisfromtheufsrestore man page. It dumps and restores on one command line
      # ufsdump 0f - /dev/rdsk/c0t0d0s7 | (cd /home;ufsrestore xf -)
    • this example skips to the 3rd dump on the tape and restores to the current directory
      # ufsrestore sxf 3 /dev/rmt/0
  • tar
    • this example creates a backup of /usr to tape
      # tar cf /dev/rmt/0cn /usr
    • this example creates a backup of /opt to file
      # tar cf /tmp/opt.tar /opt
    • this example extracts from tape
      # tar xf /dev/rmt/0
    • this example shows the contents of a tar archive from tape
      # tar tvf /dev/rmt/0
    • this example extracts the /etc/passwd and /etc/shadow files from an archive of /etc from tape
      # tar xvf /dev/rmt/0 /etc/shadow /etc/passwd
  • cpio
    • this example creates an archive to tape
      # find . | cpio -ovt > /dev/rmt/0cn
    • thisexamplelistsfilesfrom from tape
      # cpio -civt < /dev/rmt/0
    • this example extracts files from tape
      # cpio -icv < /dev/rmt/0
  • dd
    • this example dumps files to tape
      # dd if=/dev/rdsk/c0t0d0s0 of=/dev/rmt/0cn
    • this example extracts files from tape
      # dd if=/dev/rmt/0 of=/dev/rdsk/c0t0d0s0
  • mt
    • this example rewinds a tape
      # mt -f /dev/rmt/0 rew
    • this example rewinds and ejects a tape
      # mt -f /dev/rmt/0 rewoffl
    • thisexampleretensions a tape (occasionally corrects i/o errors)
      # mt -f /dev/rmt/0 retension

Documentation Resources

  • Useful man pages:
    • ufsdump(1M)
    • ufsrestore(1M)
    • tar(1)
      • chroot(1M)
    • cpio(1)
      • ls(1)
      • find(1)
    • dd(1M)
    • mt(1)
      • st(7D)
    • archives(4)
  • Useful SunSolve SRDB's and InfoDoc's
      How to do a disk-to-diskcopyviaufsdump/tar under Solaris 2.X. Info Docs: 16311
    • Primary Boot Disk Emergency Backup and Restore. Info Docs: 20812
    • Moving filesystems and boot devices with ufsdump and ufsrestore. Info Docs: 17234
    • ufsdump aborts with "SIGSEGV( ) ABORTING!". Symptoms and Resolutions: 10879
    • Copying a filesystem using ufsdump w/o a tape drive. Info Docs: 14067
    • Central Startup for Remote System Dumps. Info Docs: 20031
    • ufsdump remotely not working, cannot connect to tape host. Symptoms and Resolutions: 19168
    • Tape drive parameters in device name. Info Docs: 14066
    • A ufsdump/ufsrestore tutorial. Info Docs: 21351
    • How can you force tar to restore to a relative path? Info Docs: 18015
    • how to back up the root partition using "cpio" command. Symptoms and Resolutions: 7031


  • all utilities
    • i/o error
      • clean the tape drive
      • retension the tape ( mt -f /dev/rmt/? retension)
      • tape is bad
    • ran dump and nothing is on the tape
      • ls -l /dev/rmt* look for any files that are very large and not links example: ufsdump 0f /dev/rmt0cn or ufsdump 0f /dev/rmt/ocn
  • ufsdump/ufsrestore
    • accessingremote device fails
      • local host is not /.rhosts on the remote machine.
    • Answering the set owner mode question
      • never answer yes It will set the owner of all restored files to root.
      • There is no method of keeping this question from being asked.
  • tar
    • cd /tmp, did tar xvf and no files are there.
      • The archive was done with absolute pathing. Files were restored to their absolute path
    • i cannot tar to /dev/diskette
      • stop /usr/sbin/vold
  • dd
    • my filesystem was corrupt, did a newfs and restored from dd archive. Corruption is back.
      • dd operates on a block level, corruption was in the archive and put back on the filesystem.

Sample backup scheme

  • Always suggest usingufsdump andufsrestore
    • daily backup scheme to local tape
      • Do full backup on Sunday
      • Do level 5 incremental backups the rest of the week
        • this will reduce restore time in the event of disaster recovery
        • a level 5 everyday will backup all data newer or modified since Sunday's full backup. Therefore restoring several days worth of incrementals is not nessesary.
  • Steps to take
    • gather raw device info.Typicaly from /etc/vfstab. Sometimes customers will have filesystems that aremountedviarc script.
      • via /etc/vfstab
        • grep rdsk /etc/vfstab|grep -v "#"|awk '{print $2}'
      • via mount command
        • mount|grep dsk|awk '{print $1}'
          • ufsdump will translate the mount point to the raw device
    • perform backups via a script or command line with the following basic syntax. It will perform a level 5 backup of each raw fs in /etc/vfstab, update the /etc/dumpdates file, and log the backups to /var/log/mmdddumplog file.
      # for VOL in `grep rdsk /etc/vfstab|grep -v "#"|awk '{print $2}'`
      > do
      > echo "starting dump of $VOL" >> /var/log/`date +%m%d`dumplog
      > ufsdump 5fu /dev/rmt/0cn $VOL >> /var/log/`date +%m%d`dumplog 2>&1
      > echo >> /var/log/`date +%m%d`dumplog
      > done
      # mt rewoffl