Re: DG for nologging

From: Arjen Visser <>
Date: Thu, 8 Mar 2018 09:22:23 +1300
Message-Id: <>

4) the DR secondary can be used to host sandbox test/dev DBs, with the understanding they'll be blown away in the event of a "grey swan" event (unplanned outage), where a failover is executed

Regards Arjen

> On 8/03/2018, at 8:02 AM, Andrew Kerber <> wrote:
> The problem I have always had with SAN replication (as a dba) is that we end up relying on people outside of our control, sys admin, network, storage personnel, to keep the data up to date, and we really lack the ability to validate the status on a daily basis.  I like dataguard because I have full access to logs and status, can see what is going on, know when there are problems, and typically have the ability to fix the problems.  With SAN replication you are relying on someone else to take care of everything.
>> On Wed, Mar 7, 2018 at 12:32 PM, Arjen Visser <> wrote:
>> Some disadvantages of SAN:
>> 1)With database SAN replication you are replicating database data 3 times so quite inefficient and requiring more bandwidth. Once for all the changes in the data files, once for replicating redo, and once for replicating archive logs. With a standby database you are only replicating the changes once.
>> 2)You do not know if your SAN replicated database will start if you really need it. With a standby database it is always running and ready to take over.
>> 3) The replicated SAN database cannot be used for anything. The standby database can be used for offload reporting, offloading backups, feeding ETL etc.
>> Regards, Arjen

>>> On 7/03/2018, at 11:10 PM, Upendra nerilla <> wrote:
>>> A small detour on the SAN replication..
>>> I'm trying to understand the advantages and disadvantages of SAN replication over Data guard..
>>> I felt Data guard is very specific (to the DB replication task), it can validate the recoverability of the database continuously. SAN replication on the other hand, is useful in replicating complex application configuration to the DR site.. Also with SAN replication, we loose the ability to go point-in-time in the DR site (if the need arises?).
>>> Also if multiple databases are being replicated with the same SAN replication group, we are unable to recover each of the database to its own point-in-time..
>>> Please share any feedback or thoughts
>>> Thanks
>>> From: <> on behalf of Mladen Gogala <>
>>> Sent: Tuesday, March 6, 2018 7:36 PM
>>> To:
>>> Subject: Re: DG for nologging
>>> +2
>>>> On 03/06/2018 09:15 AM, Sheehan, Jeremy wrote:
>>>> +1 for SAN replication.

>>> --
>>> Mladen Gogala
>>> Database Consultant
>>> Tel: (347) 321-1217
> -- 
> Andrew W. Kerber
> 'If at first you dont succeed, dont take up skydiving.'

Received on Wed Mar 07 2018 - 21:22:23 CET

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