APAR status
Closed as documentation error.
Error description
The primary node ensures that a log page is not sent to any of RSS nodes until it has been recieved by the HDR. This is required since the HDR is the first choice for failover in the cluster. If the RSS goes ahead of HDR in terms log replay, then in the event of failover it will not be able to sync up with the new primary. If the HDR is offline, the primary will send the logs to RSS. But once the HDR reconnects, the primary will stop sending the logs to RSS till the HDR is caught up. Both these behaviors need to be documented clearly to avoid confusion. It could be necessary to add following in Admin Guide , under section 'Comparison of RS Secondary Servers and HDR Secondary Servers': "The HDR will always be the most log advanced server among the non-shared disk secondary nodes (RSS and HDR). This ensures that in the even of HDR becoming the primary, all the RSS nodes can continue to apply the logs from the new primary. If the HDR is offline, the primary server will continue to send logs to RSS. Once the HDR reconnects, the primary will make sure that its catches up and doesn't stay behind the RSS nodes."
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * All users of documentation for v11.50.xc5 and earlier. * **************************************************************** * PROBLEM DESCRIPTION: * * The prioritization of the HDR secondary server logs is not * * clear. * * * * This omission occurs in the Comparison of RS Secondary * * Servers and HDR Secondary Servers topic of the * * Administrator's Guide. * **************************************************************** * RECOMMENDATION: * * Upgrade to v11.50.xc6 documentation when available. * ****************************************************************
Problem conclusion
This information should be included in the Comparison of RS Secondary Servers and HDR Secondary Servers topic of the Administrator's Guide. In a high-availability cluster, the HDR secondary server must be the most log-advanced server among the non-shared disk secondary servers (RS secondary and HDR secondary). If the HDR secondary server becomes off line, the primary server continues to send logs to the RS secondary servers. However, when the HDR secondary comes back on line, IDS stops sending logs to RS secondary servers and prioritizes sending logs to the HDR secondary server until its log replay is ahead of the RS secondary server. This prioritization of the HDR secondary server logs is required because the HDR secondary server is the first failover choice in the cluster. If the RS secondary server logs are ahead of the HDR secondary server logs when a failover occurs, then the RS secondary server cannot synchronize with the new primary server.
Temporary fix
Comments
APAR Information
APAR number
IC63379
Reported component name
IBM IDS ENTRP E
Reported component ID
5724L2304
Reported release
B15
Status
CLOSED DOC
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-09-23
Closed date
2010-01-22
Last modified date
2010-01-22
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Applicable component levels
[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSGU8G","label":"Informix Servers"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"B15","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]
Document Information
Modified date:
22 January 2010