Re: EMC Snap Clones vs. Data Guard

From: DA Morgan <damorgan_at_x.washington.edu>
Date: Wed, 06 Apr 2005 22:35:03 -0700
Message-ID: <1112851881.860279@yasure>

rdperry3_at_bellsouth.net wrote:

> I recently accepted a production DBA position with a small company that
> has 2 rapidly growing 24/7 databases. Each database generates between
> 40 - 50GB of archive logs a day. Our hardware consists of 2 Sun 480's
> and 2 EMC Clarion CX300 storage arrays(fibre channel and ATA disks).
> Software consists of Oracle 9.2.0.5 and Solaris 9.
>
> We use RMAN to back up all of our databases. Since the production
> databases have grown beyond 1/2 terabyte, we no longer feel that RMAN
> can restore either database within the 4 hour window that management
> feels is acceptable. Two solutions are being looked at: Data Guard &
> Snap Clones.
>
> Data Guard is the preferred choice of the DBA's but the system
> engineers would like Snap Clones. Both sides offer good arguements for
> their respective positions. I would like to get some advice from
> someone that has faced a similar situation or a DBA that is currently
> using Snap Clones(pros & cons).
>

>>From a DBA standpoint, we like Data Guard because the production copy

> is on a separate server and is capturing changes that are occuring in
> the primary database. The production copy can be brought on line
> quickly if the primary needs to go down for maintenance or an
> unexpected problem occurs.
>
> The system engineers feel that we can perform 4 snaps a day(2
> alternating clones) and backup a snap view of the clone. Since
> we(DBA's) are concerned about corruption, we backup one or two snap
> views of the clone and allow RMAN to check the remaining snap views
> that occur during the day for corruption. If we find corruption, then
> we roll the the database back to the last successful backup. I feel
> that idea is too risky.
>
> If you have any suggestions, I would appreciate it. Our management
> does not want to buy another server in order to take advantage of Data
> Guard and they are concerned about additional Oracle licenses. We
> recently found out from our Oracle rep that we do not need licenses for
> the physical standby databases because the primary licenses will
> transfer in the event of a production outage. Even though it appears
> that Data Guard is a cheaper solution(purchase another server to host 2
> databases with less expensive disks), we appear to be headed down a
> path of a more expensive solution(reorganize data files, upgrading
> storage arrays, training, & licenses).

I'd still go with RMAN. I'd want to recover Oracle objects ... not disk blocks.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)

Received on Thu Apr 07 2005 - 00:35:03 CDT