Diskless linux system with unionfs for an educational computer center
Hideo Masuda, Akinori Saitoh, Michio Nakanishi, Seigo Yasutome · 2005
The total cost of ownership is a major concern for computer centers that maintain hundreds of PCs. From our experience, it would be most important to reduce hardware faults, particularly the troubles of hard disk drives. This paper describes how we built our educational computer system using diskless PCs. Before constructing our system, the following items were listed as the objectives of client PCs: (1) run Linux, (2) work without local HD, (3) deploy a single OS image to all PCs, (4) be easy to update the OS image, (5) be applicable to as many device configurations as possible, (6) become clients for unix servers (Linux, Solaris, AIX, etc.), and (7) use open sources. We chose Vine Linux 3.1, which is a derivative of RedHat Linux and is well organized for Japanese language environment. To satisfy (3) and (5), we introduced unionfs which has stackable file system feature. The system directories and files dependent on each PC such as /tmp, /dev, /var, /etc/mtab, and /etc/fstab are generated as memory files systems in the boot procedure, and are stacked on the common OS image using unionfs. Since this stack mechanism was implemented only by adding some hook codes to /etc/rc.d/rc.sysinit, our idea, we believe, is applicable to other Linux distributions. Our educational computer system consists of 8 servers, 12 boot servers and 500 diskless PCs, and is now in operation.