From what I can find the LCC's for the 15 and 25 slot DAE's are the same for VNX1 an VNX2.  The 25 disk DAE is the same part number for VNX1 and VNX2.  It looks like the 15 disk DAE is the same also, but the part numbers are slightly off. I\ It appears that it should be possible to use the DAE's from the VNX1 to the VNX2. For the disks in the VNX1, you would need to check the Drive and Flare Matrices  [URL]  glen
I am retiring some VNX5300s, and I also have some VNX2 arrays that are not 'fully loaded'. I know that the disks are largely interchangable between the two families, but I haven't found any documentation that suggests that either a controller swap, or an upgrade using the older DAEs is possible.  I would like to know if I can use one or more DAEs from the 5300 to augment the disk count on a VNX2.  If they are not compatible I would *guess* it would come down to something about eh LCC modules or something similar, as both are 6Gb SAS enclosures with physically identical backplanes.
Will a DAE from a VNX5300 work with a VNX2 system VNX5400/5600...?