Neverfail for SQL Server

Businesses demand high availability and The Never-fail Group's Neverfail for SQL Server provides it, with server-level and site-level protection for Microsoft SQL Server, as well as automatic failover capability. Neverfail runs on Windows Server 2003 Standard and Enterprise Editions, and Windows 2000 Server SP4, and it supports SQL Server 2000 SP3a and later.

I tested Neverfail between two servers running on the same subnet with a 100MB LAN connection. (Neverfail also includes a Low Bandwidth Module for use in WAN scenarios.) My primary and secondary servers were running Windows 2003 and SQL Server 2000 SP4.

Setup involved many steps, including some manual configuration of the network, but it went smoothly. Neverfail installed the software on the primary and secondary servers and initialized the replication environment, including the Neverfail Heartbeat Management Client. You can also install it on an administrative workstation. This client lets you set up parameters for controlling automatic failover, and it can initiate manual failover and failback. Web Figure 1 shows the Neverfail status and control screen.

Neverfail uses queued asynchronous replication to replicate data from the primary to the secondary server. I tested switchover capabilities and found that the manual failover took approximately 20 seconds to complete, plus another 10 seconds for the SQL Server service to start up. After I pulled the plug on the primary server, it took Neverfail about 15 seconds to determine that the server was unavailable and another 30 seconds to complete the failover before SQL Server was active on the secondary server.

In spite of the lengthy setup time, Neverfail worked well, and the failover process was reliable and quick.