Using udev to simplify HP Serviceguard for Linux configuration, March 2014

Technical white paper | Using udev to simplify HP Serviceguard for Linux configuration

If you are using multipath devices (DM devices), append the following rule to the

/etc/udev/rules.d/10-HP-Local.rules file:

SUBSYSTEM==”block”, KERNEL==”dm*”, PROGRAM=”/lib/udev/scsi_id

--page=0x83 --whitelisted --replace-whitespace

--device=/dev/%k”,

RESULT==”360060e80042747000000274700000315”,

SYMLINK=”hpdev/mylink-dm”

Where 360060e80042747000000274700000315 is the output of

“/lib/udev/scsi_id --page=0x83 --whitelisted

--replace-whitespace /dev/dm-1” command

Suppose there exists a softlink from /dev/mapper/mpath1 to /dev/dm-1 and /dev/mapper/mpath1 has

a partition /dev/mapper/mpath1p1. If there exists a softlink from /dev/mapper/mpath1p1 to

/dev/dm-2, append the following rule in /etc/udev/rules.d/10-HP-Local.rules file:

SUBSYSTEM==”block”, KERNEL==”dm*”, PROGRAM=”/bin/sh /root/myscript.sh /dev/%k”,

RESULT==”360060e80042747000000274700000315”,

SYMLINK=”hpdev/mylink-dmp1”

Where 360060e80042747000000274700000315 is the output of

“/lib/udev/scsi_id --page=0x83 --whitelisted

--replace-whitespace /dev/dm-1” command

and the following is the output of “cat /root/myscript.sh” command:

#!/bin/sh

device=$1

devname=”/dev/mapper/”`/sbin/dmsetup info ${device} | /bin/grep “Name” |

/bin/awk ‘{print $NF}’`

pat=”p[0-9]+$”

if [[ $devname =~ $pat ]]; then

dev=`/bin/echo ${devname} | /bin/sed -r -e ‘s/_part[0-9]+$//’ -e

‘s/p[0-9]+$//’`

/lib/udev/scsi_id --page=0x83 --whitelisted --replace-whitespace ${dev}

Note:

You have to add the extra rule only for Red Hat 6 and Red Hat 5 if the disk has partitions. For Novell SLES 11 SP1 and Novell

SLES 11 SP2, the rules mentioned in the respective sections suffice for the disks having partitions also.

Note:

On Red Hat 5, udev rules cannot be written for multipath devices (DM device).

Note:

Delete the blank lines from the /etc/udev/rules.d/10-HP-Local.rules file. The blank lines have non-printing

characters that cannot be interpreted by udev. Blank lines and comment lines beginning with “#” can then be added. Write

rule for one disk in one line. Do not use newline character within a rule.

Creating links for persistence

You can create a single link or multiple links for persistence.

To create a single persistence link, enter the following command:

For Red Hat 5:

# udevtrigger