First - we are currently using physical standby for the OLTP. It has worked well. We are migrating the HW from Teradata to Oracle and the business requirements are that both the OLTP and the WH environments be available remotely and be able to continue to be updated remotely. Congress gets antsy if we tell them that they have to wait for their information after a fatality because we have to rebuild the database (think: Sago Mine accident in 2006). With the warehouse being partially sourced directly by the OLTP system through materialized views, how, using DataGuard, can you keep both sites current in both environments? I know you can set up data guard OLTP(local) -> OLTP(remote) and WH(local) -> WH(remote). Or, OLTP(local) -> OLTP(remote) and both the local and remote WH refreshing from the local OLTP. The difficulty, as I see it, is getting the WH(remote) to sync with the OLTP(remote) when/if that situation occurs. It appears that SRDF would easliy allow that remote WH sync to remote OLTP to continue should it be needed. I'm not sure data guard would support that transition as easily. Steve Smith Desk: 303-231-5499 Fax: 303-231-5696 -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Baumgartel, Paul Sent: Wednesday, January 23, 2008 2:50 PM To: oracle-l Subject: RE: EMC's SRDF vs Oracle DataGuard I second Jeremiah's comments. The decision to use SRDF here was made by others (probably non-DBAs) a long time ago. I'd prefer DataGuard for the reasons cited. Paul Baumgartel CREDIT SUISSE Information Technology Prime Services Databases Americas One Madison Avenue New York, NY 10010 USA Phone 212.538.1143 paul.baumgartel@xxxxxxxxxxxxxxxxx www.credit-suisse.com -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Jeremiah Wilton Sent: Wednesday, January 23, 2008 4:14 PM To: 'oracle-l' Subject: RE: EMC's SRDF vs Oracle DataGuard Baumgartel, Paul wrote: > ...you must consider the hit your write performance will take, especially given the > great distance between locations. The laws of physics dictate a delay proportional > to the distance the bits have to travel I think the advantages of DataGuard over SRDF are pretty overwhelming. First of all, with Dataguard, you can create a decoupled, asynchronous duplicate site that is almost completely recoverable to the present point in time. With SRDF, in order to assure that the database will even open, you need to be in synchronous mode, which imposes a network penalty for every single logfile and datafile write. For heavy OLTP applications the impact could be dramatic. SRDF will not protect you against a wide variety of failures that DataGuard will, such as: - An errant process that writes over, deletes, or corrupts Oracle datafiles - User/admin errors and logical corruption: Dataguard can run with an apply delay In addition, with Dataguard you have the ability to query and easily back up the standby with no impact to the primary. There have got to be a half dozen other advantages to DG over SRDF that I haven't thought of. Hopefully if my SRDF experience is outdated, those with more contemporary experience will correct me. Best of all, a DG deployment will survive any future migration to another storage vendor. With SRDF you lock yourself in with EMC. Hope this helps, Jeremiah Wilton ORA-600 Consulting http://www.ora-600.net -- //www.freelists.org/webpage/oracle-l ============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ============================================================================== -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l