4.1.0 HP PolyServe Software for Microsoft SQL Server administration guide (T5392-96074, October 2010)

is specified as the Default Coordinator, HP PolyServe Software cannot virtualize
MSDTC. (Note that if MSDTC is virtualized and the Default Coordinator is then
set to a Remote Host, the MSDTC will no longer be managed by the Virtual SQL
Server.)
The following limitations exist when using a Virtual SQL Server to manage MSDTC.
• Because only one MSDTC resource exists per machine, you can define MSDTC
support for only one Virtual SQL Server per machine. You can, however, define
other Virtual SQL Servers that do not support MSDTC.
• If two MSDTC-enabled Virtual SQL Servers share the same backup and both Vir-
tual SQL Servers fail, the first server to come up will lock the MSDTC resource,
preventing the other Virtual SQL Server from starting.
• You cannot use COM+ components or MSMQ on a node where MSDTC has
been virtualized.
Policy: The policy determines the failback action that the Virtual SQL Server will take
following a failover to a backup node.
• AUTOFAILBACK. This policy is intended to return the Virtual SQL Server to its
original configuration, or as close to it as possible. After the Virtual SQL Server
fails over to a backup node, the ClusterPulse process watches the health of the
nodes higher in the list of servers for that Virtual SQL Server. When the health of
one of these nodes is equal to or greater than the backup node where the Virtual
SQL Server currently resides, the Virtual SQL Server will automatically attempt to
fail back to that node.
• NOFAILBACK. This policy is intended to minimize failovers and is the default.
The Virtual SQL Server remains active on the backup node until a “healthier”
node becomes available, at which point the Virtual SQL Server fails over to that
node. (On a “healthier” node, more of the services associated with the Virtual
SQL Server will be up than on the node currently hosting the Virtual SQL Server.
“Up” includes the probe statuses UP and Standby.)
Network Interfaces Available/Members: Move the interfaces on which the Virtual
SQL Server should be configured from the Available column to the Members column.
The first interface that you select is the primary interface. The other interfaces that
you select are backups. You can use the up and down arrows to reorder the interfaces
on the Members column.
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