SAME - Striping And Mirroring Everything

Just a note for myself in respect to ASM.

(1) Striping -  an ASM file is stripped and distributed across all the disks(disk 1~8)  in a ASM diskgroup(+DATA).  As a disk is added or removed to +DATA, ASM will rebalance the file contents(extents) among all the remaining disks within the group.

(2) Mirroring is what "Failure Groups" thing is about 

ASM mirrors(duplicates/copies) all the contents(extents) of an ASM file. It stores the original contents(extents) and the copied contents in separate sub groups, so-called "Failure Groups" inside of the same ASM diskgroup(+DATA). 

       - Normal redundancy (2 way mirroring) --> ASM creates one duplicate copy

       - High redundancy (3 way mirroring) --> ASM creates two duplicate copies.

       - External --> no mirroring. ASM assumes that mirroring is done EXTERNALLY.

 ** Each failure group has one copy of any given ASM file content(extent).