Thanks Ilmar for sharing nice points.
Sanjay
On Saturday, May 2, 2015 3:07 AM, Ilmar Kerm <ilmar.kerm@xxxxxxxxx> wrote:
Hi
We are running storage replication offsite (in ASYNC mode) and we are currently
working on replacing it with dataguard. Replicated databases are around 25TB.
* We are also running ASM, every time we need to add/remove disk from ASM there
is a huge amount of data that needs to be replicated (ASM rebalance). Initially
added double/triple amount of free space didn't last very long, since the
databases grew much faster that expected :)
* We are running in ASYNC, if the replication lags the modifications are put
into replication journal. If this journal gets 80% full or more, storage starts
to throttle down IO on the source luns. From the database perspective it was a
confusing problem to troubleshoot the first time. Also this problem is quick to
arrive when doing ASM rebalance.
Ilmar
On Sat, May 2, 2015 at 5:19 AM, Sanjay Mishra <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
Can anyone share their views on the following on Real practical experience with
the setup in their environment. I had worked with dataguard but never with
Storage Replication for Disaster recover.
Some points for the required environment which can affect or help in providing
or sharing the experience
- Oracle 11g 2-Node RAC setup using ASM on both Primary and DR site
- Database size range from 1-5Tb
- Database has lots of DML activites on daily basis
Questions:
- What is the best option to be used for Disaster Recovery when has to
choose Storage Replication vs DataGuard for RAC setup and if can provide why
you think one preferred over other as per your experience ?
- Does there can be issue if Primary storage or server crashed and Recovery
either failed to start the Datbase on DR or lost some data ? Keeping in mind
that we are working in SYnc Mode.
- Is Storage mirroring can be setup so that both Primary and Remote storage
is almost SYNC like Synchronous Data Giuard Setting ?
- Is it possible that we may loose the DR location and Storage Replicated
environment failed to start ?
- Which one is faster to bring Database live, Storage mirrored DR env or
Dataguard based environment?
- How to go back or switch back to original Primary when you have done
switchover initially to DR location ? In Oracle Dataguard we can go back using
Flashback DB feature and reinstantiate the database
- Any other Pros and Cons for both option as well as any good Link to be
checked.
TIASanjay
--
Ilmar Kerm
