20.1. Synopsis

No matter what disks you have, there are always potential problems:

• They can be too small.

• They can be too slow.

• They can be too unreliable.

One way some users safeguard themselves against such issues is through the use of multiple, and sometimes redundant, disks.

In addition to supporting various cards and controllers for hardware RAID systems, the base FreeBSD system includes the Vinum Volume Manager, a block device driver that implements virtual disk drives.

Vinum provides more flexibility, performance, and reliability than traditional disk storage, and implements RAID-0, RAID-1, and RAID-5 models both individually and in combination.

This chapter provides an overview of potential problems with traditional disk storage, and an introduction to the Vinum Volume Manager.