As I said, and as Chris was intending to say ... you cannot go from a RAID 5 to a RAID 10 without backing up, deleting array, creating new array, restoring data.
Hello Guru's I have a Dell PE2950 with RAID5 config (4x 73Gb SAS), Windows Server 2003 R2, Standard Edition OS & 4Gb RAM, PERC 6/i Integrated.  My customer is requesting to upgrade the memory to 16Gb RAM and expand the HDD capacity to 200Gb with RAID 10 config since this has more writing speed (not so sure) .  As my initial suggestion, in order to expand the RAM, I need to upgrade first the OS to Windows Server 2003 64-bit and add the additional 12Gb of RAM.  Also, I am planning to add 2x 73Gb SAS disk to catch up on the 200Gb HDD requirement.  Based on the Capacity planning tool that my vendor generously lend to us... the report shows that we have a bottleneck on I/O utilization.  As I have mentioned earlier we are currently running on RAID 5 and planning to migrate to RAID 10.  Does this plan makes sense? I appreciate any advise you can give me. Thank you,  
Dell PE2950 RAID5 migration to RAID 10