3.6.0 MxDB for SQL Server Installation and Administration Guide (5697-7088, December 2007)

Chapter 5: Configuration and Operation 64

You can use the Timeout and Failure Severity attribute to change the

failover/failback behavior. There are three settings:

NOFAILOVER,

AUTORECOVER, and NOAUTORECOVER.

NOFAILOVER. When the monitor probe fails, the Virtual SQL Server does

not fail over to a backup node. This option is useful when the monitored

resource is not critical, but is important enough that you want to keep a

record of its health. To use this option, you must also specify

IGNORE as

the Event Severity on the Scripts tab.

AUTORECOVER. If the Virtual SQL Server policy is AUTOFAILBACK,

when the probe fails, the ClusterPulse process automatically begins

failover of the associated Virtual SQL Server to a backup node. Failback

occurs in accordance with the policy setting for the Virtual SQL Server

(either

AUTOFAILBACK or NOFAILBACK). See “Configure Virtual SQL

Servers” on page 54 for a description of these settings.

NOAUTORECOVER. When the probe fails, the ClusterPulse process

automatically begins failover of the associated Virtual SQL Server to a

backup node. The monitor is then disabled on the original node. If the

Virtual SQL Server policy is

AUTOFAILBACK, you will need to manually

reenable the monitor before failback can occur. This option is useful when

integrating MxDB for SQL Server with a custom application, where

certain application-specific actions must be taken before the failback can

occur.

Service Priority: The service priority is used when the ClusterPulse

process fails over Virtual SQL Servers. Service priorities are natural

numbers, with 0 (zero) representing the highest priority and higher

numbers representing lower priorities. If multiple failures prevent

ClusterPulse from placing a Virtual SQL Server on a node where all of its

associated services are available, ClusterPulse next looks for a server

where the associated service with the highest priority is available. By

default, all service monitors have a priority of 0.

Probe Type: The probe type is set to single-probe for Virtual SQL Server

monitors. A single-probe monitor performs the probe function only on

the node where the monitor instance is active. The monitor instance is

activated on the node where the associated Virtual SQL Server is