25.2.2. Persistently activating FCP LUNs

The above instructions described how to activate FCP LUNs dynamically in a running system. However, such changes are not persistent and do not survive a reboot. How you make the changes to the FCP configuration persistent in your Linux system depends on whether the FCP LUNs belong to the root file system. Those required for the root file system need to be activated very early during the boot process by the initramfs to be able to mount the root file system. Cio_ignore is handled transparently for persistent device configurations and you do not need to free devices from the ignore list manually.

25.2.2.1. FCP LUNs that are part of the root file system

The only file you have to modify for adding FCP LUNs that are part of the root file system is /etc/zipl.conf followed by a run of the zipl boot loader tool. There is no more need to recreate the initramfs.

Red Hat Enterprise Linux provides a parameter to activate FCP LUNs early in the boot process: rd_ZFCP=. The value is a comma-separated list containing the device bus ID, the WWPN as 16 digit hexadecimal number prefixed with 0x, and the FCP LUN prefixed with 0x and padded with zeroes to the right to have 16 hexadecimal digits.

The following example zipl.conf is for a system that uses physical volumes on partitions of two FCP LUNs for an LVM volume group vg_devel1 that contains a logical volume lv_root for the root file system. For simplicity, the example shows a configuration without multipathing.

[defaultboot]
default=linux
target=/boot/
[linux]
image=/boot/vmlinuz-2.6.32-19.el6.s390x
ramdisk=/boot/initramfs-2.6.32-19.el6.s390x.img
parameters="root=/dev/mapper/vg_devel1-lv_root 
rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a000000000 
rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a100000000 
rd_LVM_LV=vg_devel1/lv_root rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 
SYSFONT=latarcyrheb-sun16 KEYTABLE=us cio_ignore=all,!0.0.0009"

To add another physical volume on a partition of a third FCP LUN with device bus ID 0.0.fc00, WWPN 0x5105074308c212e9 and FCP LUN 0x401040a300000000, simply add rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a300000000 to the parameters line of your boot kernel in zipl.conf, for example:

[defaultboot]
default=linux
target=/boot/
[linux]
image=/boot/vmlinuz-2.6.32-19.el6.s390x
ramdisk=/boot/initramfs-2.6.32-19.el6.s390x.img
parameters="root=/dev/mapper/vg_devel1-lv_root 
rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a000000000 
rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a100000000 
rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a300000000
rd_LVM_LV=vg_devel1/lv_root rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 
SYSFONT=latarcyrheb-sun16 KEYTABLE=us cio_ignore=all,!0.0.0009"

Run zipl to apply the changes of /etc/zipl.conf for the next IPL:

# zipl -V
Using config file '/etc/zipl.conf'
Target device information
Device..........................: 08:00
Partition.......................: 08:01
Device name.....................: sda
Device driver name..............: sd
Type............................: disk partition
Disk layout.....................: SCSI disk layout
Geometry - start................: 2048
File system block size..........: 4096
Physical block size.............: 512
Device size in physical blocks..: 10074112
Building bootmap in '/boot/'
Building menu 'rh-automatic-menu'
Adding #1: IPL section 'linux' (default)
kernel image......: /boot/vmlinuz-2.6.32-19.el6.s390x
kernel parmline...: 'root=/dev/mapper/vg_devel1-lv_root rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a000000000 rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a100000000 rd_ZFCP=0.0.fc00,0x5105074308c212e9,0x401040a300000000 rd_LVM_LV=vg_devel1/lv_root rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us cio_ignore=all,!0.0.0009'
initial ramdisk...: /boot/initramfs-2.6.32-19.el6.s390x.img
component address:
kernel image....: 0x00010000-0x007a21ff
parmline........: 0x00001000-0x000011ff
initial ramdisk.: 0x02000000-0x028f63ff
internal loader.: 0x0000a000-0x0000a3ff
Preparing boot device: sda.
Detected SCSI PCBIOS disk layout.
Writing SCSI master boot record.
Syncing disks...
Done.