VERITAS Volume Manager 4.1 Troubleshooting Guide

Chapter 1 11

1 Recovery from Hardware Failure

Introduction

Veritas Veritas Volume Manager (VxVM) protects systems from disk and other hardware

failures and helps you to recover from such events. This chapter describes recovery

procedures and information to help you prevent loss of data or system access due to disk and

other hardware failures.

If a volume has a disk I/O failure (for example, because the disk has an uncorrectable error),

VxVM can detach the plex involved in the failure. I/O stops on that plex but continues on the

remaining plexes of the volume.

If a disk fails completely, VxVM can detach the disk from its disk group. All plexes on the disk

are disabled. If there are any unmirrored volumes on a disk when it is detached, those

volumes are also disabled.

NOTE Apparent disk failure may not be due to a fault in the physical disk media or

the disk controller, but may instead be caused by a fault in an intermediate or

ancillary component such as a cable, host bus adapter, or power supply.

The hot-relocation feature in VxVM automatically detects disk failures, and notiﬁes the

system administrator and other nominated users of the failures by electronic mail.

Hot-relocation also attempts to use spare disks and free disk space to restore redundancy and

to preserve access to mirrored and RAID-5 volumes. For more information, see the

Administering Hot-Relocation chapter in the VERITAS Volume Manager Administrator’s

Guide.

Recovery from failures of the boot (root) disk requires the use of the special procedures

described in “Recovery from Boot Disk Failure” on page 45.

Listing Unstartable Volumes

An unstartable volume can be incorrectly conﬁgured or have other errors or conditions that

prevent it from being started. To display unstartable volumes, use the vxinfo command. This

displays information about the accessibility and usability of volumes: