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

1 Introduction
HP PolyServe Software for Microsoft SQL Server (HP PolyServe Software) provides
high availability for SQL Server databases located on PSFS cluster filesystems. High
availability support is also provided for MS DTC and Microsoft SQL Server
2005/2008 Analysis Services.
Virtual SQL Servers
HP PolyServe Software uses Virtual SQL Servers to provide failover support and high
availability. A Virtual SQL Server “virtualizes” the network name and IP address
associated with a particular SQL Server/Instance. That is, rather than using the
network name and IP address of an actual server, a Virtual SQL Server is created
and assigned a unique name/IP-address pair. Up to 16 SQL instances can be
associated with each Virtual SQL Server.
Clients access the databases associated with an instance via the Virtual SQL Server
name or IP address; they do not need to know which node is running the SQL instance.
When you configure a Virtual SQL Server, you will need to specify an active, or
primary, node and one or more passive, or backup, nodes. The SQL instances
associated with the Virtual SQL Server must be installed on all of these nodes. The
Virtual SQL Server is active on the primary node, and SQL database requests are
serviced from there. On failure, the ClusterPulse process (provided with Matrix Server)
will fail over, or migrate, the Virtual SQL Server to one of the designated backup
servers, where it will continue to provide access to the same PSFS filesystem data
under the same name/IP-address pair.
Active-Passive architecture
HP PolyServe Software uses an Active-Passive architecture for high-availability. For
example, when you virtualize a SQL server instance in a two-node cluster, you declare
one node to be the active, or primary, node for the instance and the second node
to be the backup. The high-availability engine provided with HP PolyServe Software
for Microsoft SQL Server then creates the appropriate profiles for the virtualized
instance.
HP PolyServe Software for Microsoft SQL Server 4.1 administration guide 9