EMC Snap Clones vs. Data Guard

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). Received on Wed Apr 06 2005 - 10:14:40 CDT