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2#
发表于 2012-3-8 18:01:14
10g 不支持临时将 physical standby 转换为 LOGICAL STANDBY 的 " ALTER DATABASE RECOVER TO LOGICAL STANDBY KEEP IDENTITY;" 这是 11g的新特性
logical standby 是支持 rolling upgrade 的
Logical Standby (DataGuard)
Goal:
Minimal downtime
Concept:
Upgrade will be done on the standby first
Afterwards: Switchover - standby will be now prod system
Now upgrade on ex-prod - switchover back to start layout
Pros&Cons:
Downtime ~2min fpr both switchovers
No changes of the OS platform possible
Logminer has some datatype restrictions
Some effort to setup and prod must be at least 10.1.0.3
But beginning with 11g:Transient Logical Standby utilizes an existing Physical Standby database for the rolling upgrade process
步骤:
1. Start with logical standby setup.
2. Use DBUA to upgrade the Logical Standby
3. Turn on log transport to synchronize (this could take some time to catch up)
(At this point the users have no idea of any changes)
4. Switchover primary to standby, upgrade the former primary. If systems are identical then we could stop right there. If the original standby is less powerful or otherwise shoudln‘t be the primary, we can switch back.
Keep in mind that this concept doesn‘t support all datatypes. |
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