I would like to see if anyone has previous experience and/or a strong opinion one way or another concerning design.  I am running two pSeries hosts with AIX 7.1 clustered using PowerHA.  Lets say I have (20) EFD's available on the symmetrix.  I use a R5 3+1 and then stripe those together to make a large meta-lun.  When presented to AIX this gives one hdisk where we assign a volume group, LV's and file systems.  Time passes and all is good but we are eating up this space.  We purchase another (20) EFD's.  We now have two options.

• Option 1) Create additional R5 3+1's and stripe those against the existing meta. 
  • Will I hit a drive limit? 
  • Will this cause a major performance headache during the re-stripe for the current hot file system? 
  • Will the AIX cluster handle growing the VG without an outage?
  • Are there other considerations?
• Option 2) Create a new striped metalun with R5 3+1's (same as the original set) and add that to AIX.  This will add another hdisk.  Essentially this will be host based concatenation (rather than on the Symmetrix).
  • This will not stripe data but since these are EFD's do we really care?
  • Are we creating any sort of a redundancy issue or data integrity issue now or later down the road by having data blocks randomly spread across these hdisks?
  • Will the AIX cluster handle this without an outage?