HP 3PAR RedHat and Oracle Linux Implementation Guide

1. For RHEL 5.x, when prompted by the install CDs or DVD after the host comes up, at the boot
prompt, type the following command:
boot: linux mpath
This command communicates that multiple paths are connected from the storage to the host.
2. Respond to all the prompts during the install process by selecting the default settings.
When the installation completes, the host is rebooted.
Modifying the /etc/multipath.conf File
NOTE: RHEL 6 uses the default install for a SAN boot.
During an RHEL SAN boot install using the mpath option, the /etc/multipath.conf file is
automatically edited by the install processes. As part of the /etc/multipath.conf edits
performed during install, the global multipath option user_friendly_names enabled.
Note that using the user_friendly_names option can be problematic in the following situations:
If the system root device is using multipath and you use the user_friendly_names option, the
user-friendly settings in the /var/lib/multipath/bindings file are included in the initrd.
If you later change the storage setup, such as by adding or removing devices, there is a mismatch
between the bindings setting inside the initrd and the bindings settings in
/var/lib/multipath/bindings.
CAUTION: A bindings mismatch between initrd and /var/lib/multipath/bindings
can lead to a wrong assignment of mount points to devices, which can result in file system corruption
and data loss.
Use the alias option to override the user_friendly_names option for the system root device
in the /etc/multipath.conf file.
Verify that the SAN boot disk created is /dev/sda.
# fdisk -l -u /dev/sda
Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders, total 62914560 sectors
Units = sectors of 1 * 512 = 512 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 63 208844 104391 83 Linux
/dev/sda2 208845 62910539 31350847+ 8e Linux LVM
Identify the scsi_id of the boot disk via:
# scsi_id -g -u -s /block/sda
350002ac001b90031
This identified that 350002ac001b90031 is the WWID of the boot disk in the above example.
Establish an alias name of mpath0 for the WWID of the boot disk using multipath entries in
/etc/multipath.conf.
For RHEL 5.0 through RHEL 5.5, the contents of /etc/multipath.conf file should be edited
as in the following example if the HP 3PAR StoreServ Storage array is running HP 3PAR OS 3.1.1
or later.
128 Booting the Host from the HP 3PAR StoreServ Storage