Pillar Axiom: Linux Servers Using Device-Mapper Fail to Mount Axiom SAN LUNs at Boot Time

Asset ID:	1-72-1391138.1
Update Date:	2012-09-04
Keywords:

Solution Type Problem Resolution Sure

Solution 1391138.1 : Pillar Axiom: Linux Servers Using Device-Mapper Fail to Mount Axiom SAN LUNs at Boot Time

Applies to:

Pillar Axiom 500 Storage System - Version Not Applicable to Not Applicable [Release N/A]
Pillar Axiom 300 Storage System - Version Not Applicable to Not Applicable [Release N/A]
Pillar Axiom 600 Storage System - Version Not Applicable to Not Applicable [Release N/A]
Information in this document applies to any platform.

Symptoms

When using Redhat Linux to mount Axiom LUNs using device-mapper with and without APM, the following issue applies:

Newly installed system with SAN devices attached fails to detect filesystem(s) at boot time. During reboot the logical volumes or file systems on the SAN are not accessible.

Cause

This issue is generated when device-mapper has not started and but lvm already wants to activate the volume groups on it or the operating system wants to access the file systems.

For more information, refer to the follow article:

https://access.redhat.com/kb/docs/DOC-7226

Solution

This problem is best solved by using the "_netdev" parameter in /etc/fstab for the device. It ensures that logical volumes are only activated and the filesystem mounted when the service netfs is started. Since this service is only started later in the boot process, it gives the SAN enough time to finish the process of presenting its LUNs.

Add the "_netdev" parameter as a mount option in /etc/fstab for all affected file systems.

== For LVM file systems, change ==

/dev/vgsan/lv01 /storage ext3 defaults 1 2

INTO

/dev/vgsan/lv01 /storage ext3 defaults,_netdev 1 2

== For normal file systems, change ==

/dev/sda1 /storage ext3 defaults 1 2

INTO

/dev/sda1 /storage ext3 defaults,_netdev 1 2

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