NOTE
Configuring your Environment for Software RAID
Using Persistent Device Names
Using Persistent Device Names
When there is a disk related failure and subsequent reboot, there is a possibility that the devices are renamed. Linux names disks in the order they are found. The device that was /dev/sdf may be renamed to /dev/sde if any “lower” device is failed or removed. As a result, you cannot activate the MD device with the original name.
HP requires that the device names be persistent to avoid reorientation after a failure and reboot. For more information on creating persistent device names, see the Using udev to Simplify HP Serviceguard for Linux Configuration white paper that is available at the following location:
http://docs.hp.com
When creating persistent device names, ensure that the same udev rules file exists in all the nodes. This is necessary for the symlinks to appear and point to the correct device. Use these persistent device names wherever there is a need to specify the devices for extended cluster configuration or during recovery process after a failure. A persistent device created based on the instructions in the document mentioned earlier will have a device name that starts with /dev/hpdev/.
The name of the MD device must be unique across all packages in the cluster. Also, the names of each of their component udev devices must also be unique across all nodes in the cluster.
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