3.1.2 Matrix Server Administration Guide

Chapter 5: Configure the SAN 65

sandiskinfo --dynvol_properties

Dynamic Volume: psv1 Size: 2439M Stripe=Unstriped

Subdevice: 20:00:00:04:cf:13:38:18::0/5 Size: 490M psd1p5

Subdevice: 20:00:00:04:cf:13:38:18::0/2 Size: 1950M psd1p2

Dynamic Volume: psv2 Size: 490M Stripe=32K/optimal

Subdevice: 20:00:00:04:cf:13:38:18::0/7 Size: 490M psd1p7

Dynamic Volume: psv3 Size: 490M Stripe=8K/optimal

Subdevice: 20:00:00:04:cf:13:38:18::0/10 Size: 490M psd1p10

Matrix Server MPIO

Matrix Server uses multipath I/O (MPIO) to eliminate single points of

failure. A matrix can include multiple FibreChannel switches, multiple

FC ports per server, and multiported SAN disks. This configuration

provides multiple paths for I/O between matrix servers and SAN disks.

When you start Matrix Server, it automatically configures all paths from

each matrix server to the storage devices. On each server, it then uses the

first path it discovered for I/O with the SAN devices. If that path fails,

Matrix Server automatically fails over the I/O to another path.

The mxmpio command can be used to display status information about

MPIO devices or to control the path used for I/O. With the exception of

enableall and disableall, all commands take PSD device names to

operate on specific devices. If you do not specify a PSD device, the

command operates on all devices.

Enable or Disable Failover for a Server

A matrix server can use multiple FC ports to connect to the FibreChannel

fabric. If the FC port or FC switch currently being used for I/O should fail,

Matrix Server will by default fail over the I/O to another FC port/FC

switch path.

You can use the following command to control whether this failover

behavior can occur on a particular node. Run the command on the server

where you want to change the failover behavior. (Matrix Server starts

with failover enabled.)

# mxmpio enableall|disableall