Re: EMC storage replication
- From: goran bogdanovic <goran00@xxxxxxxxx>
- To: K Gopalakrishnan <kaygopal@xxxxxxxxx>, fuadar@xxxxxxxxx
- Date: Thu, 2 Dec 2010 17:54:14 +0100
Gopal, Faud,
Thanks for inputs ... I appreciate a lot.
I am aware of the fact that SAN replication on block level is not aware of
'content' of Oracle datablocks i.e. if there is a corruption on primary the
EMC Replication will happily replicate it to secondary SAN.
With this I can live. The reason is following: we plan to use it for
not-so-critical DB-systems - for critical ones we have DataGuard ;-)
If the corruption happens and being detected within DB backup retention
policy, we can always restore to state before corruption and re-load the
rest of the data - business logic allows this. Since we already have EMC
Replication license, I see no reason to spend money on additional DG license
for such systems.
But here is the key-point to detect corruption within DB Backup retention
policy ... if not, hmmm ... I have to think about this.
What makes me worry, are the points from Faud.
1. What do you mean when you say "Application Architecture needs to be
there"? What exactly? TAF? FAN? or similar?
2. "Frequent testing of this infrastructure needs to be there" - would you
please specify more this point?
Best Regards,
Goran
On Thu, Dec 2, 2010 at 5:11 PM, K Gopalakrishnan <kaygopal@xxxxxxxxx> wrote:
> Goran,
>
> You got great inputs so far. Just a word of caution, the EMC replication is
> at the array level and it has no knowledge about Oracle datablocks. If
> there is a corruption (believe me, it happens) at the oracle datablock
> level, storage array will not aware of that and propagates the corruption to
> the secondary (or remote) SAN. You have to periodically validate the
> readiness of the DR site when SAN mirroring is used.
>
> You don't need to do this additional step when DG is used as it validates
> blocks during transfer and recovery..
>
> -Gopal
>
>
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