Configuring the Linux operating system for IBM z Systems® hosts
You must configure the Linux® operating system before you can use z Systems® hosts with the system.
Before you begin
Procedure
After the prerequisite tasks are complete, use the following general steps to configure your z Systems hosts that are running the Linux operating system:
- Zone the host to the system on the Fibre Channel SAN. For more information, see the zoning details and zoning examples topics in the Configuring section of the help.
- Create the host on the system using the worldwide port names (WWPNs). Map the volumes to the host, as required.
- Configure your Linux system for FCP attachment. See the latest versions of the Linux on zSeries Device Drivers and Installation Commands for the Linux Kernel and Device Drivers, Features, and Commands for the Linux Kernel publications for additional information.
- See your host publications for additional configuration tasks.
Multipath support for IBM z Systems hosts
You must install multipathing software on all z Systems hosts that are attached to the system.
For more information about using the logical volume manager or the multipathing tools package with z Systems hosts that run Linux kernel 2.4 or Linux kernel 2.6, see the documentation at the following website:
Multipathing configuration maximums for LVM and mp-tools
When you configure, keep in mind the maximum configuration for the logical volume manager (specifically, LVM1) for the Linux operating system.
Logical volume manager
| Object | Maximum | Description |
|---|---|---|
| Number of volume groups | 99 | The number of volume groups that can be defined per host |
| Physical volumes per volume group | 256 | The maximum number of physical volumes that can be assigned to one volume group |
| Paths per physical volume | 16 | The maximum number of paths to each PV |
| Logical volumes | 256 | The total number of logical volumes that are supported by LVM1 (because of the 256 minor number limit of the kernel) |
The number of paths per physical volume is limited to eight paths with Kernel 2.6.
Clustered system support on hosts running the Linux operating system
The system does not provide clustered system support on hosts that run the Linux operating system.
SAN boot support on IBM z Systems hosts
On a SCSI LUN, you can complete an initial program load (IPL) process.
IPL processes on SCSI LUNs can fail because there is no path failover capability during the boot process. See the latest How to use FC-attached SCSI devices with Linux on z Systems publication for more information about using IPL processes with z Systems hosts.
Defining the number of disks on IBM z Systems hosts
When you define the number of disks on z Systems hosts that are running the Linux operating system, you are provisioning capacity for configured disks.
On the Linux operating system, a device node is used for each path to the disk and a second device node is used for the path grouped device. The maximum number of devices depends on your Linux configuration.
System configuration for IBM z Systems hosts
Each attached system LUN has a set of device files in the /dev Linux directory.
These device files are intended to be used only by the multipath tools. Allowing them to be used directly by your system or applications can produce data inconsistencies. Instead, configure your system and applications to use the device nodes that are created by the multipath tools.
The maximum number of devices depends on your Linux configuration. See the latest Linux on zSeries Device Drivers and Installation Commands for the Linux Kernel and Device Drivers, Features and Commands for the Linux Kernel publications for additional information about multipathing support.