There are a number of possibilities.  Depending on how much free space you have in the first group.  If there's enough free space you can vacate the member with 200GB drives.  It will be reset, add in new Dell/EQL drives and run setup and add it back into group.   If not, It might also be possible to rent/borrow an array chassis from your sales rep.  Then you can do same process.  Shutdown group. Put 200GB drives in loaner chassis and connect to switch and power up.  New drives go in your original chassis.  Add that to group.  vacate out member with 200GB drives.  That's the preferred way.   Re: Replication.  How are you planning on replicating from the DR SAN to the Promise array?  
Hello, I work for a school district up in Alaska and I am their server specialist. We have 3 PS4000 san arrays. San Group1- Server Farm -has two PS4000 members, both have 16 drives. -one array has 16 1TB disks, and the other array has 16 200GB disks   San Group2- Direct Replication target, Pool Storage -has 1 ps4000 member, configured with 16 1TB drives   What i would like to do is replace the drives in the array that currently has 200gb disks. That would give us the increased capacity i am looking for. My question is if there is anyway to upgrade the drives that would be easier than my process below:   Wipe out san group2 which is our DR target Replicate all data from the "server farm" to the freshly wiped DR target upgrade and reconfigure the san with 200 gig drives to 1TB drives replicate data back from DR target to "server farm" and enjoy extra disk space   I also have another promise array that i plan on duplicating the production data when it is soley stored on the DR target, that way if the pool blew up, we wouldnt lose all our data during the upgrade process :)   Thanks for any advice/comments you can provide!   Sam Powell Server Specialist Kodiak Island Borough School District  
Increasing drive capacity on EQL PS4000 array