Specifications

14 – Configuring and Monitoring a Redundant Server System

330 R400

Server Redundancy Fast Failover Configuration

Normally Station reconnect time is approximately 30 seconds. It is possible to

tune server and Station redundancy timeout parameters to achieve approximately

10 second Station reconnect time (also known as fast failover).

Configuring fast failover is only recommended for high performance servers

running on high performance networks, because it increases:

• The traffic that the Stations and Servers put onto the network

• The Servers’ susceptibility to failover from disruptions on the network

One way to improve failover time without affecting network performance is to

define IP addresses in the hosts files so that IP address resolution is faster (see

“Making IP Address Resolution Faster” on page 333).

If you want to configure fast failover, you set parameters for:

• The time until the backup server becomes primary after it detects that the

primary is down (see “Time Until Backup Server Becomes Primary” on

page 330)

• The time until the Server allows a new Station connection to use a Station

number after a Station connection fails (see “Time Until Server Disconnects

Station” on page 331)

• The time until a Station fails over to the backup network after a connection

to the Server fails (see “Time Until Stations Fail Over to Backup Network” on

page 332)

Time Until Backup Server Becomes Primary

To tune the time until the backup server becomes primary after it detects that the

primary server is down, you reset the number of messages permitted to be lost

before failover occurs. The following steps must be performed on both the

primary and backup Server:

Open a Command Prompt window and enter the command

hscserver /database to stop the PlantScape Server.

Isolate the network between the servers from other network traffic.

Edit the PSW00 line in the redundancy configuration file,

\server\user\redun.hdw

• For fast failover, add IDLE=5 READ=10 to the PSW00 line

• For normal operation, delete the IDLE and READ values from the

PSW00 line, or set the default values IDLE=10 READ=15.

plscpcg.book Page 330 Monday, May 28, 2001 10:11 AM