How RAID handles disk failures

Disk failure with a hot spare disk

About this section

This section describes how the filer reacts to a disk failure when a hot spare disk is available.

Filer replaces disk with spare and reconstructs data

If a disk fails, the filer

Replaces the failed disk with a hot spare disk
Reconstructs in the background the missing data onto the hot spare disk
Logs the activity in the /etc/messages file on the root volume
Sends an autosupport message

During reconstruction, file service can slow. The filer does not shut down automatically.

Caution
After the filer is finished reconstructing data on the hot spare disk, replace the failed disk with a new hot spare disk as soon as possible so that there is always a hot spare disk available in the system. For information about replacing a disk, see Chapter 5, Disk Management.

If a second disk fails and there is no hot spare disk available, contact Network Appliance Technical Support.

Note
If there is a media failure during a reconstructing state, the filer panics with a fatal error but first marks the volume as inconsistent. On reboot, the volume will be made restricted, reconstruction will resume, and media errors will be ignored on the volume. If this situation occurs, call Network Appliance Technical Support.

For more information

In addition to disk failure and hot spare disk replacement, the /etc/messages file on the root volume logs any failure in a periodic check of the hot spare disk. For more information, see the na_sysconfig(1) and na_messages(5) man pages.