VxVM supports the combination of striping above mirroring. This combined layout is called a striped-mirror layout. Putting mirroring below striping mirrors each column of the stripe. If there are multiple subdisks per column, each subdisk can be mirrored individually instead of each column.
As for a mirrored-stripe volume, a striped-mirror volume offers the dual benefits of striping to spread data across multiple disks, while mirroring provides redundancy of data. In addition, it enhances redundancy, and reduces recovery time after disk failure.
Figure: Striped-mirror volume laid out on six disks shows an example where a striped-mirror volume is created by using each of three existing 2-disk mirrored volumes to form a separate column within a striped plex.
Figure: How the failure of a single disk affects mirrored-stripe and striped-mirror volumes shows that the failure of a disk in a mirrored-stripe layout detaches an entire data plex, thereby losing redundancy on the entire volume.
When the disk is replaced, the entire plex must be brought up to date. Recovering the entire plex can take a substantial amount of time. If a disk fails in a striped-mirror layout, only the failing subdisk must be detached, and only that portion of the volume loses redundancy. When the disk is replaced, only a portion of the volume needs to be recovered. Additionally, a mirrored-stripe volume is more vulnerable to being put out of use altogether should a second disk fail before the first failed disk has been replaced, either manually or by hot-relocation.
Compared to mirrored-stripe volumes, striped-mirror volumes are more tolerant of disk failure, and recovery time is shorter.