IBM SG24-5131-00 manual Shared LVM Component Configuration

Change/Show Characteristics of a SCSI Adapter

SCSI adapter	ascsi1
Description	Wide SCSI I/O Control>
Status	Available
Location	00-06
Internal SCSI ID	7	+#
External SCSI ID	[6]	+#
WIDE bus enabled	yes	+
...
Apply change to DATABASE only	yes

The command line version of this is:

# chdev -l ascsi1 -a id=6 -P

As in the case of the SCSI-2 Differential Controller, a system reboot is required to bring the change into effect.

The maximum length of the bus, including any internal cabling in disk subsystems, is limited to 19 meters for buses connected to the SCSI-2 Differential Controller, and 25 meters for those connected to the SCSI-2 Differential Fast/Wide Adapter/A or Enhanced SCSI-2 Differential Fast/Wide Adapter/A.

3.4 Shared LVM Component Configuration

This section describes how to define the LVM components shared by cluster nodes in an HACMP for AIX cluster environment.

Creating the volume groups, logical volumes, and file systems shared by the nodes in an HACMP cluster requires that you perform steps on all nodes in the cluster. In general, you define the components on one node (referred to in the text as the source node) and then import the volume group on the other nodes in the cluster (referred to as destination nodes). This ensures that the ODM definitions of the shared components are the same on all nodes in the cluster.

Non-concurrent access environments typically use journaled file systems to manage data, while concurrent access environments use raw logical volumes. This chapter provides different instructions for defining shared LVM components in non-concurrent access and concurrent access environments.

Cluster Hardware and Software Preparation 81