Recovering the DiskSuite Configuration

The /etc/lvm/md.cf file is a backup file of the DiskSuite configuration for a "local" diskset. Whenever you make a configuration change, the md.cf file is automatically updated (except for hot sparing). You never edit the md.cf file directly.

If your system loses the information maintained in the metadevice state database, and as long as no metadevices were created or changed in the meantime, you can use the md.cf file to recover your DiskSuite configuration.

The md.cf file does not maintain information on active hot spares. Thus, if hot spares were in use when the DiskSuite configuration was lost, those metadevices that were hot-spared will likely be corrupted.

How to Use the md.cf File to Recover a DiskSuite Configuration

Only use this procedure if you have experienced a complete loss of your DiskSuite configuration.

1. Recreate the state database replicas.

   Refer to Chapter 1, Getting Started for information on creating state database replicas.

2. Make a backup copy of the /etc/lvm/md.tab file.

3. Copy the information from the md.cf file to the md.tab file.

4. Edit the "new" md.tab file so that:

   • All mirrors are one-way mirrors. If a mirror's submirrors are not the same size, be sure to use the smallest submirror for this one-way mirror. Otherwise data could be lost.

   • RAID5 metadevices are recreated with the -k option, to prevent reinitialization of the device. (Refer to the metainit(1M) man page for more information on this option.)

5. Run the metainit(1M) command to check the syntax of the md.tab file entries.

   # metainit -n -a

6. After verifying that the syntax of the md.tab file entries is correct, run the metainit(1M) command to recreate the metadevices and hot spare pools from the md.tab file.

   # metainit -a

7. Run the metattach(1M) command to make the one-way mirrors into multi-way mirrors.

8. Validate the data on the metadevices.