Specifications
Installing the fibre-channel adapter drivers
Perform the following steps to install the fibre-channel adapter drivers.
Note: This is an example of how to install the fibre-channel adapter drivers.
1. Type mkdir /usr/src/qlogic
2. Type mv [download location]/[driver source] /usr/src/qlogic
3. Type tar -xzf [driver source]
4. Type cd /usr/src/linux
5. Type make modules
6. Type make modules_instal
7. Type make OSVER=linux-2.4.x SMP=1 where x represents kernel version, and
SMP=1 if running multi-processors
8. Type mkdir /lib/modules/2.4.x/kernel/drivers/scsi where x is your kernel
version
9. Type cp qla2x00.o /lib/modules/2.4 x/kernel/drivers/scsi
10. Type insmod qla2x00
Configuring the ESS with the QLogic QLA2200F or QLogic QLA2300F
host adapter card
To configure the host adapter card, use the IBM Enterprise Storage Server
StorWatch Specialist.
Number of disk devices on Linux
The maximum number of devices that are supported on a Linux system is 128. The
standard Linux kernel uses a major and minor number address mechanism. A
special device file represents each disk device. For each default, there is a
maximum of 16 partitions per disk. The major and minor numbers are 8-bit.
There are eight major numbers that are reserved for SCSI devices. Fibre-channel
attached devices are handled as SCSI devices. The major numbers are 8, 65, 66,
67, 68, 79, 70 and 71.
There are 256 minor numbers available for each of the eight major numbers. The
following formula provides the maximum number of devices under Linux.
Number of devices = (number of major#) x (number of minor#) / (number of partitions)
Number of devices=8x256/16 = 128
There are several Linux extensions available to address this limitation. One
approach is to use the major and minor number address spaces in different ways.
Some of the minor number address space for the partitions is used for the major
number address space to allow more devices with less partitions.
You an also use devfs (device file systems). Devfs uses a 32-bit device identifier
which allows you to address many more. It shows only the devices that are
available on the system, instead of listing device files for devices that are not
attached to the system. Devfs is backwards compatible, mounts over /dev and uses
UNIX like device identification. Here is an example /dev/scsi/host/bus/target/lun
86 ESS Host Systems Attachment Guide
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|