double stiping for ASM Oracle.

thank you Boom for the information.

I had this PDF and from that one only I got the idea about the double striping.

however, how to I check if my (210 Symm devices (16.86 GB each)) is double striped or not.

ASM already is doing striping by nature. however, having a double striping on the array devices themselves is an enhancement to ASM

You might be using the ASM default/external redundancy as the array takes care of the protection/mirror part. Also ASM does not have a FOURTH option to look for.. So most of the ASM installation go with default/external and IMHO it should not cause performance issue by the "doublt stripping:" you are suspecting..

One can configure ASM disk groups to have no redundancy (external), two-way mirroring (normal), or three-way mirroring (high). In the case of normal and high mirrors, good practice suggests having fail groups that talk to different controllers for performance and fail-safe reasons.

• In the case of external redundancy, ASM does not do any software mirroring, but only stripes its files across all the disks that belong to the disk group that does external redundancy.
  
• In the case of normal redundancy, ASM does two-way mirroring, meaning that ASM maintains two copies of the data through software mirroring.
  
• In the case of high redundancy, ASM does three-way mirroring, maintaining three copies of the data through software mirroring.