Disk failure without a hot spare disk

About this section

This section describes how the storage system reacts to a disk failure when hot spare disks are not available.

Storage system runs in degraded mode

When there is a single-disk failure in RAID4 enabled aggregates or a double-disk failure in RAID-DP enabled aggregates, and there are no hot spares available, the storage system continues to run without losing any data, but performance is somewhat degraded.

Attention
You should replace the failed disks as soon as possible, because additional disk failure might cause the storage system to lose data in the file systems contained in the affected aggregate.

Storage system logs warning messages in /etc/messages

The storage system logs a warning message in the /etc/messages file on the root volume once per hour after a disk fails.

Storage system shuts down automatically after 24 hours

To ensure that you notice the failure, the storage system automatically shuts itself off in 24 hours, by default, or at the end of a period that you set with the raid.timeout option of the options command. You can restart the storage system without fixing the disk, but it continues to shut itself off periodically until you repair the problem.

Storage system sends messages about failures

Check the /etc/messages file on the root volume once a day for important messages. You can automate checking of this file from a remote host with a script that periodically searches the file and alerts you of problems.

Alternatively, you can monitor AutoSupport messages. Data ONTAP sends AutoSupport messages when a disk fails.

Storage system reconstructs data after disk is replaced

After you replace a disk, the storage system detects the new disk immediately and uses it for reconstructing the failed disk. The storage system starts file service and reconstructs the missing data in the background to minimize service interruption.