List of HADR new features since original HADR release in DB2 V82. Sorted by most recent ones first.
Table of Contents
First available in V10.5 fp4 (Cancun release)
HADR is now supported on databases with columnar tables. Note that reads on standby still cannot query columnar tables.
First available in V10.5
HADR is now supported on pureScale clusters. See
HADR in DB2 pureScale environments
First available in V10.5
STANDBY_SPOOL_PERCENT reports spool usage, similar to STANDBY_RECV_BUF_PERCENT.
STANDBY_RECV_BLOCKED and STANDBY_LOG_DEVICE_FULL from HADR_FLAGS are very useful warning flags.
See also
HADR monitoring
and
HADR flags monitor element
First available in V10.1
Up to 3 standbys are supported. Now you can provide HA and DR protection to your database with a single technology. See
HADR multiple standby databases
First available in V10.1
"db2pd -hadr"
format is easier to parse.
MON_GET_HADR
table function available. New fields specifically for performance monitoring: LOG_HADR_WAIT_CUR, LOG_HADR_WAIT_ACCUMULATED, LOG_HADR_WAIT_RECENT_AVG. See also
HADR monitoring
First available in V10.1.
Static database configuration parameters for HADR will be refreshed on database startup and on HADR component startup. Therefore "stop HADR" followed by "start HADR" command on a primary database will pickup new values of HADR parameters. This allows initializing and reconfiguring HADR without downtime on the primary database. See also
HADR Config - HADR Database Configuration Parameters
First available in V10.1
Spooling allows you to specify additional space where logs can be spooled on the standby. This helps avoid back-pressure on the primary caused by sudden spikes in logging activity. See
HADR log spooling
First available in V10.1
Delayed replay helps prevent data loss due to errant transactions. See
HADR delayed replay
First available in V95fp8 and V97fp5
In this new mode, transactions on primary database will never be slowed down or blocked. See
SUPERASYNC mode
First available in V97fp5
Reads on standby can return inline XML and LOB objects. Queries on non-inline objects will still return error. This allows small LOB/XML objects to be returned by reads on standby.
First available in V97fp1 (Dec. 2009)
HADR standby database now accepts read-only queries. To enable this feature, set registry variable DB2_HADR_ROS to ON on the standby instance. For details, see
Enabling reads on standby
First available in V95fp4 and V97
When database parameter BLOCKNONLOGGED is set to YES (default NO), tables with "not logged initially" attribute or not logged LOB columns can not created, either by create table or alter table statement. See
blocknonlogged - Block creation of tables that allow non-logged activity configuration parameter
First available in V8fp17, V91fp5, and V95fp2
Db2pd -hadr option will report percentage of HADR standby buffer used. If the percentage frequently hits 100%, consider increasing buffer size. If utilization is low, consider reducing buffer size. Buffer size can be set via registry variable DB2_HADR_BUF_SIZE. For more info, see
db2pd - Monitor and troubleshoot DB2 database command
First available in V8fp17, V91fp5, and V95fp2
Registry variable to tune socket buffer size for HADR connections. This allows tuning TCP window size for HADR connection without impact on other TCP connections on the system. For more info, see
Miscellaneous variables
First available in V8fp16, V91fp4, and V95fp1
Registry variable for maximal primary logging wait time. Prevents primary logging from blocking because of slow or blocked standby. For more info, see
Miscellaneous variables
First available in V95
Database configuration parameter hadr_peer_window allows takeover with no data loss when primary failed within peer window. For more info, see
HADR peer window configuration parameter
First available in V8fp15, V91fp3, and V95.
Registry variable to bypass IP address cross check in NAT (Network Address Translation) environment. This feature allows HADR to be deployed in NAT environment. For more info, see
HADR and Network Address Translation (NAT) support