RAID 1 volumes provide a means of constructing redundant volumes, in which a partial or complete failure of one of the underlying RAID 0 volumes does not cause data loss or interruption of access to the file systems. The following example, drawing on the sample system explained in Chapter 5, Configuring and Using Solaris Volume Manager (Scenario), describes how RAID 1 volumes can provide redundant storage.
As described in Interlace Values for Stripes, the sample system has two RAID 0 volumes, each of which 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 of the disk controllers will not interrupt access to the volume. Similarly, failure of up to three individual disks might be tolerated without access interruption.