You can do this, and the performance should not be different than having all of the drives in the same DAE.  According to th Best Practices Guide it says you can gain a slight availability increase, but it doesn't mention performance (BP Guide , page 46)  -Ryan
Hi,      I have a CX4-120. RG1 is a 4+1 R5 RAID Group on the first DAE (FC 15k drives). We have 3 more FC15k drives in the next DAE currently unbound. Can I add those 3 drives to RG1 and expand and have the same performance as if all the drives were on the same DAE ? Is it best practices to do this?  Thanks,               David
Expand RAID groups with disks on different DAE