Preparing for and Recovering from a System Drive Crash 

This page shows one way you can prepare for a system drive crash, and in case you are unfortunate enough to have a system drive fail, how to recover from it.

The basic idea is to take a regular "snapshot" of your computer's system drive with the Backup facility, and save that backup on a 4mm DAT drive.  Then, if your system does fail, you can simply recover from that tape, and all the configuration files will be just as you had them during your last snapshot.

Be certain that you know the device name of your DAT drive. It may be the DLT if you have a DLT and/or are using the machine as a Networker server. Use the command mt -f /dev/tape status to verify that /dev/tape does indeed go to the intended drive. If it does not, you will need to find the tape device (in the directory /dev/rmt), and use the -t option with Backup (see the man page for more details).

To take a snapshot of a drive, put a 4mm DAT tape in your dat drive, and run the following commands:

  1. mt rewind
  2. /usr/sbin/Backup /
    1. MAKE SURE THAT YOU HAVE THE CORRECT TAPE DEVICE.
    2. The Backup program will do a full backup of the directories given in the command line.
    3. The Backup program will NOT cross filesystems, so if you specify /, only the system drive will be backed up.
  3. This should be done on a regular basis.  This is a good candidate for a cron job.
To recover from a system drive crash:
  1. Pull the drive. 
  2. Replace drive with a spare drive. 
  3. Bring up system to miniroot from OS CD-ROM. 
  4. fx and partition the drive to be a /root system drive. 
  5. Restore drive with last snapshot of the system drive. 
  6. cd /root 
  7. /usr/sbin/bru -xv -ur -j -f (tape-device -- maybe /dev/tape, maybe not) / 
  8. Bring system up and verify everything is working. 
  9. Check: 
    1. /etc/exports 
    2. /etc/passwd
    3. /var/flexlm 
    4. /etc/init.d/network 
If you also have a /usr partition, then you need to: 
  1. Pull the drive. 
  2. Replace drive with a spare 4GB drive. 
  3. Bring up the OS to multi-user mode. 
  4. fx and partition the new drive to be a 1 partition option drive. 
  5. Mount drive as /usr 
  6. Install networker4.sw.client. 
  7. Recover /usr directory using nwrecover. 
 
Silicon Graphics®
and the Silicon
Graphics logo® are
registered trademarks
of Silicon Graphics, Inc. 
Updated
November 19, 1997;
Jason Salge;
John Dickerson;
Doug Schaapveld;
Iowa State University
Iow