ASM and RAID

ASM and all Oracle Guru

I would like to know if you can shared your experience of the prefer/best practice of creating ASM diskgroups with storage subsystem like RAID.

Oracle recommends create two diskgroups, one for DATA and one for FLASHBACK. Also we all to be told that the best practice is placing redo/undo/temp in RAID 1 and database datafiles/control files in either RAID 1+0 or probably RAID5 is another option.
So base on the above scenarios,

1. Does that mean ASM DATA diskgroup will contain either RAID 1+0 or RAID 5 disks and ASM FLASHBACK diskgroup will be the place of redo/undo and temp in RAID 1 disks?
2. But we see that ASM will multiplex redo logs on both diskgroups, Is that going to have performance problem?
3. and also if you use flashback for RMAN backupset storage area, does RAID 1 good for that?
4. Will/should we mix different RAID types in the same ASM diskgroups? What's the best practice of leveraging and managing those different ASM file types (like tempfile, datafile, cheangeblock, unto, etc) with RAID where striping and mirroring are already built-in.
5. Should we create two ASM diskgroups with RAID 1 mainly for redo, undo and temp and create 1 DATA diskgroup for database data and control file on top of RAID1+0 and create another diskgroup for falshback? Which RAID type should give to flashback diskgroup or not need to stripping on disk level ? The above configuration will create more than two diskgroups in ASM instance.

Could any/all of you provide your ASM diskgroup configuration for me as references? Please advice. Many thanks for all the help.

Cindy

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