After six (6) months of study, I just come across High Availability Best Practices. This is the manual I should started with. And I discovered it by reading Data Guard Concepts and Administration for the third time.
Use a Simple Disk and Disk Group Configuration is recommended for ASM in that two (2) disk groups should be configured: +DATA and +RECO. I achieved this by being lazy.
The high performance disk layout is interesting for striping the +DATA and +RECO disk groups across the same physical disks (see Figure2-2). This is in spite of the installation manual recommending separate physical disks for each disk group.
What this means is that I am going to have to rebuild RMANDOG and then RMANCAT to use two (2) disk groups with external redundancy. Since I was using raw devices on RMANDOG, I will have to install asmlib drivers as well.
The disk layout would be:
/dev/sdc1 (2Gb) mapped to DATA1
/dev/sdc2 (6Gb) mapped to RECO1
/dev/sdd1 (2Gb) mapped to DATA2
/dev/sdd2 (6Gb) mapped to RECO2
To create the disk groups,
CREATE DISKGROUP data EXTERNAL REDUNDANCY DISK ‘ORCL:DATA1′,’ORCL:DATA2’;
CREATE DISKGROUP reco EXTERNAL REDUNDANCY DISK ‘ORCL:RECO1′,’ORCL:RECO2’;