create a temporary device group, add those 8 source devices and 8 target devices.  Create clone with -precopy, let it get to 100% and then activate.  Verify production group clone state and make sure your new devices are in the same state (probably Copied if you are doing nightly clones). At this point you are read to move them from temporary group to production group  symdg –sid 123 –g tempdg moveall proddg –rename -force   (this will move 8 source devices to prod dg) symdg –sid 123 –g tempdg moveall proddg –rename –tgt -force  (this will move 8 target devices to prod dg)
Trying to add 8 new devs and 8 new tgt's to an existing device group.  This is for our main database server that uses these clones to do a nightly backup.  The database is frozen and then a activate and recreate is run nightly.  I am concerned with adding 8 new devs/tgt's that the activate / recreate will take a significant amount of time longer and cause our main application to be down while it initially syncs these new devices.  I am also looking for the syntax to add devs and tgt's to the group once it has already been created and in use.  To create the group a few years ago I used the following syntax.  symdg create prod_clone01 -type any symdg -sid xxx -g prod_clone01 addall -devs xxx1,xxx2,xxx3,xxx4,xxx5,xxx6,xxx7,xxx8 symdg -sid xxx -g prod_clone01 -tgt addall -devs xxx9,xx10,xx11,xx12,xx13,xx14,xx15,xx16 symclone -g prod_clone01 create -tgt -nop -v symclone -g prod_clone01 -tgt activate symclone -g prod_clone01 -tgt recreate  Thanks! 
VMAX10K: Is there a way to add new devs and tgt's to an existing device group 
without causing delay in the recreation of the existing clones in the group?