RAID-1 volumes provide a means of constructing redundant volumes. Thus, when a partial or complete failure of one of the underlying RAID-0 volumes occurs, there is no data loss or interruption of access to the file systems. The following example, drawing on the scenario explained in Chapter 5, Configuring and Using Solaris Volume Manager (Scenario) and continued in Scenario—RAID-0 Volumes, describes how RAID-1 volumes can provide redundant storage.

As described in Scenario—RAID-0 Volumes, the sample system has two RAID-0 volumes. Each volume is approximately 27 Gbytes in size and spans three disks. By creating a RAID-1 volume to mirror these two RAID-0 volumes, a fully redundant storage space can provide resilient data storage.

Within this RAID-1 volume, the failure of either disk controller does not interrupt access to the volume. Similarly, failure of up to three individual disks might be tolerated without access interruption.

To provide additional protection against problems that could interrupt access, use hot spares, as described in Chapter 16, Hot Spare Pools (Overview). Specifically, see How Hot Spares Work.