When you define the number of disks on hosts running the Linux® operating system, you are allocating space for configured disks. On the Linux operating system, disks are represented as device files.
For 2.4 Linux kernels, there are 256 minor numbers that are available for each of the eight major numbers that can be used to define Linux device files. Use the following formula to define the maximum number of device files for the host system:
(Number of major numbers) x (Number of minor numbers) / (Number of partitions) = Number of devices
For example, if you have 16 partitions on a 2.4 kernel, you would have 128 devices (8 x 256 / 16 = 128).
For 2.6 Linux kernels, there are significantly more minor device numbers that are available. Because SAN Volume Controller limits you to 512 VDisks per host, you have more device numbers than can be used.