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Difference between CDP réplica and crashed application ?
Hello
We've been testing an Oracle VM (all disks as vmdk on the same datastore) recovery through CDP replica without any succes. The same VM on which a power off was applied, Oracle applies its own recovery and starts without any problem.
Is there any difference between a snapshot image restart and a "after crash" restart which could explain why the database cannot work with the replica image ?
Thanks,
Xavier
zazz2
2 Posts
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June 19th, 2011 05:00
Hello,
Thanks for your answer Alex but the question is a little different.
We wanted to validate Oracle could restart over a crash consistent VMware datastore snapshot, issued from the RP CDP journal. We've tested it 30 times and it never came up, the database hanged each time... althought the same VM powered off abruptly, restarts without any complaint. The vmware tools are not installed and therefore the power off is ... straigth forward.
Each CDP replica test gave us the Windows 2003 event ID 16, Instance XXXX has been terminated. Looking further we've noticed Oracle ARCHIVELOGS was not set, but it was to late to test it. However, without or with ARCHIVELOGS set, I really don't understand why Oracle doesn't behave similarly.
In such a situation, It becomes difficult to argue that CDP is a valid protection solution.
Best regards,
Xavier
avs
91 Posts
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June 19th, 2011 05:00
Hello
If you just make a replica without freezing I/O of Oracle you will get crash consistent replica what is same as emergency power off Oracle server.
To make application consistent replica you shoul use ALTER TABLESPACE ... BEGIN BACKUP, make a replica and ALTER TABLESPACE ... END BACKUP.
Other way to do it is using Replication Manager which could freeze Oracle DB, make a replica (bookmark in RP) and thaw Oracle.
Best regards,
Alex
avs
91 Posts
0
June 20th, 2011 01:00
Hello
I think you should engage EMC technical support
Fixing the problem requires logs from VMware, guest OS, Oracle, RP. It also requires understanding current configuration and steps you perform to make and use a replicas. It's not a forum question.
Best regards,
Alex
JamesBEMC
257 Posts
1
June 20th, 2011 02:00
Xavier
Many customers and field personnel use RecoverPoint to constantly and successfully access and bring up both application and crash-consistent copies of Oracle every day.
If the Oracle database is setup correctly in RecoverPoint in terms of consistency groups and ensuring that the target volumes are only accessible to ONE mount host and the other host-level best practices are followed, then I would expect you to have no issues.
RecoverPoint fully supports crash consistency, write order consistency, exactly the same as you would expect with a crash power-off and on of a VM.
Please do work with your EMC Technical people to ensure you have set up correctly. If issues occur after that, create a service request and support will assist in helping you and your configuration.
Thanks - James