Recovery After System Corruption

Recovery After System Corruption

If your root filesystem is damaged and your system cannot boot, you can restore your system from the Recover System option on the System Maintenance Menu. This is the menu that appears when you interrupt the boot sequence before the operating system takes over the system. To perform this recovery, you need two things:

Access to a CD that contains the IRIX release on your system.
A full system backup tape (beginning in the root directory (/) and containing all the files and directories on your system) created using the Backup and Restore window or the Backup command as described in the section "System Backups".

If you do not have a full system backup made with the Backup command or Backup and Restore window--and your root or usr filesystems are so badly damaged that the operating system cannot boot--you have to reinstall your system software and then read your backup tapes (made with any backup tool you prefer) over the freshly installed software.

You may also be able to restore filesystems from the miniroot. For example, if your root filesystem has been corrupted, you may be able to boot the miniroot, unmount the root filesystem, and then use the miniroot versions of restore, xfs_restore, Restore, bru, cpio, or tar to restore your root filesystem. Refer to the following discussions of these commands for details on how to use them.

To recover from system corruption using the Recover System option on the System Maintenance Menu, follow these steps:

When you first start up your machine or press the Reset button on the system, this message appears:
Starting up the system...
Click the Stop for Maintenance button or press <Esc> to bring up the System Maintenance menu.
Click the Recover System icon in the System Maintenance menu, or type:
4

This System Recovery menu appears or you see a graphical equivalent:

System Recovery...

Press <Esc> to return to the menu.

1) Remote Tape 2) Remote Directory 3) Local CD-ROM 4) Local Tape

Enter 1-4 to select source type, <esc> to quit,
or <enter> to start:
Enter the menu item number or click the appropriate drive icon for the IRIX release CD or software distribution directory you plan to use.
Note: As of IRIX 6.2, the Remote Tape and Local Tape options on the System Recovery window are no longer usable because bootable (miniroot) software distribution tapes are no longer supported.
1. If you have a CD-ROM drive connected to your system, enter 3 or click the Local CD-ROM icon, then click Accept to start.
  You then see a notifier prompting you to insert the media into the drive. Insert the IRIX CD that came with your system, then click Continue.
2. If you don't have a CD-ROM drive, you can use a drive that is connected to another system on the network. At the System Recovery menu, enter 2 or click the Remote Directory icon.
  When a notifier appears asking you for the remote hostname, type the system's name, a colon (:), and the full pathname of the CD-ROM drive, followed by /dist. For example, to access a CD-ROM drive on the system mars, you would type:
  
  mars:/CDROM/dist
  Click Accept on the notifier window, then click Accept on the System Recovery window.
  
  On systems without graphics, you are prompted for the host as above, then you see this menu:
  
  1) Remote Tape 2)[Remote Directory] 3) Local CD-ROM 4) Local Tape
  *a) Remote directory /CDROM/dist from server mars.
  
  Enter 1-4 to select source type, a to select the source, <esc> to quit,
  or <enter> to start:
  Press <Enter>.
3. If you are using a remote software distribution directory, enter 2 or click the Remote Directory icon.
  When a notifier appears that asks you to enter the name of the remote host, type the system's name, a colon (:), and the full pathname of the software distribution directory. For example:
  
  mars:/dist/6.2
  Click Accept on the notifier window, then click Accept on the System Recovery window.
  
  On systems without graphics, you are prompted for the host as above, then you see this menu:
  
  1) Remote Tape 2)[Remote Directory] 3) Local CD-ROM 4) Local Tape
  *a) Remote directory /dist/6.2 from server mars.
  
  Enter 1-4 to select source type, a to select the source, <esc> to quit,
  or <enter> to start:
  Press <Enter>.
The system begins reading recovery and installation from the CD. It takes approximately five minutes to copy the information that it needs. After everything is copied from the CD or remote directory to the system disk you see messages including:
************************************************************
* *
* CRASH RECOVERY *
* *
************************************************************

You may type sh to get a shell prompt at most questions

Checking for tape devices
The next message asks for the location of the tape drive that you will use to read a system backup tape you created prior to the system crash using the Backup and Restore tool on the System menu of the System Toolchest or using the Backup(1) script.
If you have a local tape device, you see this message:
Restore will be from tapename. OK? ([y]es, [n]o): [y]
tapename is the name of the local tape device. Answer y if this is the correct tape drive and n if is not.
If you have a remote (network) tape device, no tape device was found, or you answered "no" to the question in the previous step, you see this message:
Remote or local restore ([r]emote, [l]ocal): [l]
1. If you answer "remote," you have chosen to restore from the network, and you are then asked to enter the following information: the hostname of the remote system, the name of the tape device on the remote system, the IP address of the remote system, and the IP address of your system. The IP address must consist of two to four numbers, separated by periods, such as 192.0.2.1
2. If you answer "local," you have chosen a tape device that is connected to your system, and you are then asked to enter the name of the tape device.
When you see the following message, insert your most recent full backup tape, then press <Enter>.
Insert the first Backup tape in the drive, then press (<enter>, [q]uit (from recovery), [r]estart):
There is a pause while the program identifies the filesystems on the tape and attempts to mount those filesystems under /root. Then you see this message:
Erase all old filesystems and make new ones (y, n, sh): [n]

You have three choices:
1. Answer n for no. After additional prompts confirming the filesystems to be read, the files on the tape are extracted. The version of each file on the tape replaces the version, if any, on the disk even if the version on the disk is newer.
2. Answer y for yes. After additional confirming prompts and prompts about filesystem types, the system erases all of the filesystems and copies everything from your backup tape to the disk.
3. Answer sh to escape to a shell. You are now in the miniroot environment and can investigate the damage to the system or attempt to save files that have been created or modified since the backup tape was created. After exiting the shell, you have the opportunity to remake filesystems and/or read the backup tape.
After reading the full backup tape, this prompt gives you the opportunity to read incremental backup tapes:
Do you have incremental backup tapes to restore ([y]es, [n]o (none)): [n]
Insert another tape and answer y if you have additional tape, answer n otherwise.
This prompt gives you the opportunity to reboot your system if recovery is complete, begin the crash recovery process again at the beginning, or re-read your first backup tape:
Reboot, start over, or first tape again? ([r]eboot, [s]tart, [f]irst) [r]
If you are ready to reboot, answer r, otherwise choose start or first.