Multiple lun's per RAID, double stripping?

Hi
We have a scenario where we only have 1 set of physical disks available to our RAC cluster( I think its RAID 1+0 or 5+0.. the RAID is mirrored... ). I would like to know if creating multiple luns for +DATA disk group  ( all luns are coming from the same set of physical disks) causes I/O problems? 
Will creating multiple lun’s introduce unnecessary I/O overhead? Any other reasons why we shouldn’t have multiple lun’s?
what is double stripping?
Thanks
A

some of those threads are suggesting not to create more than one lun per diskgroup on the same disk or set of disks( RAID).
ASM double stripping
Re: Recommended Number LUNs for ASM Diskgroup
Re: Is it safe to increase LUN size of ASM disk online 11gR2 ?
http://kr.forums.oracle.com/forums/thread.jspa?threadID=884912
Re: ASM diskgroups and RAID
Again, it depends on how that RAID-10 is being presented to you by the storage admins. The 5x600GB LUNs could be carved out of 5 different RAID-10 arrays, which would increase the total number of spindles behind your diskgroup and therefore improve performance (assuming no other contention). Or, they may have carved all 5 LUNs out of a single dedicated array, which can still provide benefit, assuming the array has more than 10 disks. Or, even if the array only has 10 disks, it may be more cost effective for the storage admin due to a lower number of hot spares required to support a single array vs. multiple arrays (which doesn't benefit you - and this is where a potential performance different due to the double-striping vs. RAID-1 comes in). There are many variables that come into play.
Thanks

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