DataGuard9i vs Array Based Mirror

Hi,

We're trying to establish where the decision points are in picking a remote standby solution for a big Oracle installation that must have zero data loss between sites. The solutions in consideration are a physical standby DataGuard9i DB in "Maximum protection mode" vs. Disk Array based remote mirroring over a SAN (continuous access on EVA or XP arrays)

As far as which solution would get the prize for day to day (synchronous IO) performance we still need to run some tests.

My initial feel is that DataGuard is much less expensive but would be a slower
recovery in the event of a catastrophic disk failure.

Am I wrong ? Below are the points I considered. Please correct me and/or let me know what else I should be taking into consideration.

Thanks,

jamest_at_onemain.com

_PRICE and ADDED FUNCTIONALITY_

DG :
 Dataguard is bundled with Enterprise Edition Oracle - so it's sort of free.  Dataguard doesn't care how expensive the disks under it are. DG allows  read only reporting from the DR site.

Array Based Mirror :
 With storage mirroring all of your data can be in HA. Control files,  software, flat files, etc. The mirrors can be split to allow for a fast  backup or reporting. This stuff requires two big arrays and the purchase  of a CA license.

_EASE of RECOVERY_

DG :
 In the event of complete loss of the primary site disks, the DR site data  will have to be manually copied back to the primary site. This could mean  spinning backup tapes or huge remote copies over the WAN. I can't find  anything in the DG manual that would "reimage" the primary database.

Array Based Mirror:
 In the event of full scale primary site meltdown the recovery would be  relatively quick with a reverse resync of the mirrors. If the DR site is  close enough to be a fibre channel link (upto 100km ), then it could be  days quicker than the Dataguard solution.

_PERFORMANCE_
DG :
 The amount of data shipped over the WAN is limited to just logfiles but the  WAN is very slow compared to a fibre channel connection. This solution is  server based so system resources are used to provide redundancy.

Array Based Mirror :
  Storage based mirrors cause no extra load on the servers   CPU/Memory/Network.
  With array based mirroring the logs can be mirrored to the DR site over   a very fast SAN. But the immediacy of the DG data apply services   isn't in this solution. Received on Tue Apr 22 2003 - 10:39:23 CDT