Introduction

Disk hardware is evolving rapidly, and the current UNIX disk abstraction is inadequate for a number of modern applications. In particular, file systems must be stored on a single disk partition, and there is no kernel support for redundant data storage. In addition, the direct relationship between disk volumes and their location on disk make it generally impossible to enlarge a disk volume once it has been created. Performance can often be limited by the maximum data rate which can be achieved with the disk hardware.

The largest modern disks store only about 50 GB, but large installations, in particular web sites, routinely have more than a terabyte of disk storage, and it is not uncommon to see disk storage of several hundred gigabytes even on PCs. Storage-intensive applications such as Internet World-Wide Web and FTP servers have accelerated the demand for high-volume, reliable storage systems which deliver high performance in a heavily concurrent environment.

The problems
Current implementations
How Vinum addresses the Three Problems
The big picture
Some examples
Increased resilience: RAID-5
Object naming
Startup
Performance issues
The implementation
Driver structure
Availability
Future directions
References