最近开始将DB2数据库从单纯的Hacmp的模式切换到HADR+TSA+HACMP模式。

原理感觉和Oracled的DG一样，但是功能还是偏弱,目前有一些限制的地方需要注意:

1.HADR is not supported in a partitioned database environment.
2.The primary and standby databases must have the same operating system version and the same version of the DB2 database system, except for a short time during a rolling upgrade.
3.The DB2 database system release on the primary and standby databases must be of the same bit size (32 or 64 bit).
4. Reads on the standby database are not supported. Clients cannot connect to the standby database.
5. Log archiving can only be performed by the current primary database.
6. You can use Self Tuning Memory Manager (STMM) only on the current primary database.
7. Backup operations are not supported on the standby database.
8. Non-logged operations, such as changes to database configuration parameters and to the recovery history file, are not replicated to the standby database.
9. Load operations with the COPY NO option specified are not supported.
10. HADR does not support the use of raw I/O (direct disk access) for database log files. If HADR is started via the START HADR command, or the database is activated(restarted) with HADR configured and raw logs are detected, the associated command will fail.