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RE: ZFS snapshots

From: Kerber, Andrew <>
Date: Tue, 12 Dec 2006 08:31:40 -0600
Message-ID: <>

Your problem will probably be matching up the Oracle scn's. They change rapidly, and if they don't match Oracle will give you the old need media recovery message. I am not sure if you can copy them quick enough to keep all the Oracle scn's in sync. I know it can be done with the DB down, but I wouldn't count on doing it with the DB up.  

Andrew W. Kerber
Oracle DBA

"If at first you dont succeed, dont take up skydiving"

-----Original Message-----
[] On Behalf Of Donahue, Adam Sent: Tuesday, December 12, 2006 8:18 AM To:
Subject: ZFS snapshots  


Sanity check question for those familiar with ZFS.

Is there any reason, assuming all datafiles were on a single ZFS filesystem (which is the level of consistent snapshot granularity), that something like the following wouldn't work to copy a database (and refresh on a regular basis) -

        zfs snapshot data_at_n 
        zfs snapshot log_at_n 
        zfs send -i data_at_n-1 data_at_tag | rsh target zfs receive data 
        zfs send -i log_at_n-1 data_at_tag | rsh target zfs receive log 
        zfs clone data_at_n data-qa 
        zfs clone log_at_n log-qa 

Given the granularity of writes to the redo logs, I'm trying to think of how corruption might be introduced here, if it could. From what I see above, though, it would be more-or-less like a straight-forward database crash - which would on the target side would be recovered automatically during instance startup.  


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Received on Tue Dec 12 2006 - 08:31:40 CST

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