Oracle Database Tips by Donald Burleson

Oracle10g Grid Computing with RAC
Chapter 5 - Preparing Shared Storage

Storage Control Layer (SCL) Role

Importing SAN disks - shared disks need to have a partition table on them before they are imported into the matrix. Once they are imported, Matrix controls them thereafter. That is, no access to the disk can occur unless it is through the cluster file system. Matrix Server is managed via a graphical user interface however; all functionality can also be carried out at the command line through the CLI. Some useful commands are:

To import the disk:
# mx disk import <UUID>
 
To deport the disk:
# mx disk deport <UUID>
 
To display the disk information:
# sandiskinfo
 
MxS uses multi-path I/O to eliminate single points of failure and to perform I/O load balancing. The matrix can include multiple FC switches, multiple HBAs per server, and multi-ported SAN disks. When MxS is started, it automatically configures all paths. It uses the first discovered path on each server for I/O with the SAN devices. When the first path fails, MxS automatically fails over the I/O to another path. Use the command mxmpio to display and manage.