Re: EMC storage replication

  • From: William Muriithi <william.muriithi@xxxxxxxxxxxxxxxxxxx>
  • To: "goran00@xxxxxxxxx" <goran00@xxxxxxxxx>
  • Date: Thu, 2 Dec 2010 10:08:14 -0600

Goran

This is not from personal experience - Have only worked with DRDB which is the 
same animal in different skin, but I do recall reading it somewhere and sounded 
like something that can be a deal breaker.

EMC has no application knowledge and replicate everything in block level. 
Essentially, every change that happen on the primary array will be pushed to 
the secondary array even if its undesirable. So, a corruption/misconfiguration 
on your primary database would not only bring down your primary database, but 
you would shortly get alerts from scripts monitoring the backup database that 
all things are not fine there too. Dataguard  would however not replay 
corrupted logs, the replication would just fail when oracle detect that the 
logs have issues and hence save the day.

So yes, dataguard may be expensive to license and maintain that EMC 
replication, but I would not look at one as a complete replacement of the 
other.  This is straight from my memory, which from experience is not that 
great, so research on it and update us should I be misinforming the list


William

On 2010-12-02, at 10:16 AM, goran bogdanovic wrote:

> Thanks you all for answers!
> 
> The idea behind is following:
> On primary Data Center we will be having 'primary' database attached to EMC 
> SAN.
> All disk changes should via EMC Replication sent to SAN in second Data Center 
> located in different town (I have been assured by network guys we have enough 
> bandwith for this).
> On second Data Center we should be having 'secondary' (kind of 'standby') 
> server connected to 'replicated' SAN - 'active - passive' configuration.
> 
> In case that 'primary' server or Data Center 'fails', we should be able to 
> activate 'secondary' server and "Le voilà !" ... the system is running again 
> ;-)
> 
> sound simple and EMC sales state it works ;-) ... and I always double check 
> statements comming from sales people.
> 
> @Jaffar,
> convincing management is not an option ;-)
> 
> 
> Best Regards,
> Goran
> 
> 
> On Thu, Dec 2, 2010 at 3:55 PM, Fuad Arshad 
> <fuadar@xxxxxxxxx<mailto:fuadar@xxxxxxxxx>> wrote:
> Goran,
> We are using both SRDF/A and Server Cloning Processes for replication.
> The process is fairly simple  with the most of the coding/scripting  effort .
> One of the Issues we've encounted is while the Clone process is running There 
> is a very high amount  of I/O Being Done as the Disk Frame level. Since a 
> clone  can only be done in the Same Frame level. This can cause Database 
> Bottlenecks albeit for a small period of time .
> We've Move to Data guard  due to these issues.
> May i Ask what  is the requirement .  If Offloading Backups is the need. I've 
> found Physical Dataguard to be better than  EMC Cloning.
> SRDF/A is a different product set from EMC and it allows for between 
> Frame/Datacenters replication.  It is a fairly costly solution though.
> While Oracle will certify an Oracle Database Running on an EMC Frame. It will 
> not certify a 3rd Part product.
> The technology is called Split mirror  and the EMC Product is Time Finder.
> Meta link Note Exploiting EMC Timefinder and Oracle Recovery Manager [ID 
> 204719.1]
> 
> 
> 
> ________________________________
> From: goran bogdanovic <goran00@xxxxxxxxx<mailto:goran00@xxxxxxxxx>>
> 
> To: ORACLE-L <oracle-l@xxxxxxxxxxxxx<mailto:oracle-l@xxxxxxxxxxxxx>>
> Sent: Thu, December 2, 2010 6:58:54 AM
> Subject: EMC storage replication
> 
> Hi all,
> 
> at the place where I work, management would like to implement EMC Replication 
> (as we have EMC SAN's) for our databases between two Data Centers instead of 
> DataGuard for certain DB-systems.
> According to EMC sales, the process is certified by Oracle although I didn't 
> find any reference on Metalink (could be also, I didn't search it well).
> If someone (out there ;-) ) is already using it, I would appreciate if you 
> could tell me your experiences and possible pitfalls regarding implementation.
> 
> Best Regards,
> Goran
> 

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