HP UX Encrypted Volume and Filesystem (EVFS) Recovering from EMD Corruption, EMD Backup Directory

Recovering from EMD Corruption

EVFS stores one backup image of the EMD for each EVFS volume. When you change the owner of an EVFS volume, or add or delete user keys for a volume, EVFS updates the EMD. Before EVFS updates the EMD, it stores a backup copy of the current EMD. The evfsvol restore command restores the backup copy of the EMD for an EVFS volume.

Use the following procedure to restore a backup copy of an EMD:

1.For data consistency, stop all applications accessing the data. You can use the fuser -cucommand to determine the processes accessing files, and the fuser -ckucommand to terminate the processes. See fuser(1M) for more information.

If the data is used by system processes, you might need to terminate the processes by changing the system runlevel to single-user level with the shutdown utility. See shutdown(1M) for more information.

2.(Optional) Create a cleartext backup copy of the data, or copy the cleartext data from the EVFS volume to another disk device using a utility such as fbackup, cp, or tar.

3.If you have a file system mounted on the EVFS volume, use the umount command to unmount the file system. See umount(1M) for more information.

4.Use the following command to disable encryption and decryption on the target volume: evfsvol disable [-kkeyname] evfs_volume_path

See “Disabling Encryption/Decryption Access to EVFS Volumes” (page 81) for more information.

5.Use the following evfsvol restore command to restore the EMD: evfsvol restore evfs_volume_path

where:

evfs_volume_path Specifies the absolute pathname for the EVFS volume device file, such as /dev/evfs/vg01/lvol5,

/dev/evfs/vx/dsk/rootdg/vol05, or /dev/evfs/dsk/c2t0d1.

6.Use the following command to enable EVFS operation for the volume: evfsvol enable [-kkeyname] evfs_volume_path

See “Enabling Encryption and Decryption Access to EVFS Volumes” (page 80) for more information.

7.If you had a file system mounted on the EVFS volume, use the mount command to remount the file system. See mount(1M) for more information.

8.restart applications, as necessary.

EMD Backup Directory

By default, EVFS stores EMD backup images in the directory /etc/evfs/emd. See “Step 3: (Optional) Modifying EVFS Global Parameters” (page 42) information about changing this directory path. Ensure there is enough space in this directory to store all the system's backup EMDs from the encrypted volumes. The storage requirement is approximately 1 MB per encrypted volume.

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