HP 3PAR RedHat and Oracle Linux Implementation Guide

1. Before building the ramdisk, add the following HBA parameters to the/etc/modprobe.conf
file, depending on your version of RHEL. These HBA options settings are required for desired
multipath failover/failback operation:
• For RHEL 6:
NOTE: The /etc/modprobe.conf file has been deprecated in RHEL 6. In order to
make changes to the ramdisk, follow these steps:
1. Create the /etc/modprobe.d/modprobe.conf file.
2. If the HP 3PAR array is running HP 3PAR OS 3.1.1 or later, add the following line:
options lpfc lpfc_devloss_tmo=14 lpfc_lun_queue_depth=16
lpfc_discovery_threads=32
• For RHEL 5:
options lpfc lpfc_devloss_tmo=14 lpfc_lun_queue_depth=16
lpfc_discovery_threads=32
• For RHEL 4:
options lpfc lpfc_nodev_tmo=14 lpfc_lun_queue_depth=16
lpfc_discovery_threads=32
NOTE: If the HP 3PAR array is running an HP 3PAR OS version earlier than 3.1.1, set the
lpfc_devloss_tmo or lpfc_nodev_tmo setting to 1 instead of 14 for the corresponding
RHEL version.
2. To increase or modify maximum number of LUNs the OS can discover, add SCSI layer
parameters to /etc/modprobe.conf.
NOTE: RHEL 6.x does not require this change. The /etc/modprobe.conf file has been
deprecated in RHEL 6.
For example, for the OS to support 256 LUNs per target port:
options scsi_mod max_luns=256
NOTE: The kernel loads the SCSI drivers from ramdisk in the order in which they are defined
in the modprobe.conf file and assigns the SCSI device entries (sda, sdb) in ascending
order starting with the first entry for each entry where a SCSI device exists. If the host has a
SCSI boot disk, it must obtain device entry sda since those entries are hard coded in the
bootloaders. Therefore, the scsi_hostadapter entry that supports the boot disk must appear
first in the /etc/modprobe.conf file.
3. Change the /etc/modprobe.conf file after making the driver topology changes.
The following example is for an RHEL 6.x or RHEL 5.x connected to an HP 3PAR StoreServ
Storage array running HP 3PAR OS 3.1.1 or later. If the HP 3PAR StoreServ Storage array
34 Configuring a Host with Fibre Channel