Thursday, March 27, 2008

Archive Gaps due to Firewall Connection Timeouts

Shipment of log files between primary and standby data-guard nodes, intermittently fails withORA-12570 TNS:packet reader failure, when the connection is going via a firewall.

Firewall is removing the network connection from under the Oracle Net layer. If the network connection has no connectivity and a timeout filter is enabled, then the connection can be lost.

Set the SQLNET.EXPIRE_TIME=X parameter in the SQLNET.ORA file on both servers.This enables Dead Connection Detection (DCD). When enabled, this sends a probe packet from the server (Standby node) to the client(Primary node) every X about of minutes, for the value of X set in the SQLNET.ORA file.

Set on both servers, so any change such as switchover between nodes, ensures the parameter is set for both directions.

More on metalink note 550103.1 , 151972.1 and 257650.1