Allow adding FlashSystems Disk to Mirrored ASP without requiring them to be mirrored

With RAID no issue to migrate to FlashSystems. 1) Add FS disks, 2) Drain Internal disks. 3) Copy LS data.

Mirroring disallows this as you must stay mirrored! With Mirroring we need the ability to somehow set a switch to allow the system to add device type 2145 disk units to the ASP without requiring mirrororing. This includes the copy of the LS disk unit.

With the capabilities of Flash Systems storage many customers are moving this way. If a customer has RAID protection for their system this is a no-brainer.
1) Connect the FlashSystem
2) Add all disk (- load source) from the FlashSystem to the ASP
3) Remove all internal disks from the System thus moving the data to the FlashSystem.
(Note that this point the customer system is still in FULL PRODUCTION!)
4) IPL to DST, Copy load source, IPL back to IBM i. You be on FlashSystem. And if you happen to be also migrating to POWER9 you simply make that last IPL from Power9!
And not only did no fingers ever leave your hand no data was ever unprotected during this migrations.

Now when disk is Mirrored, Oh Crap. (Darn, Rats, whatever, my selected term [Deleted] gets [Deleted]).
1) You need TWICE the disk on the FlashSystem to get even close.
2) Create TWICE as much storage as you need for the migration.
3) Add TWICE as many disks as you really want.
4) Add these to the ASP of course since Mirrororing is active it will do twice as many writes and take twice as many longs to do this.
5) Load source. Crap. gotta end mirroring to do the Copy Disk Unit Data which leaves the disk exposed during this time and adds extra time to the process.
6) Once everything is done all the extra disks now need to be removed from the host on the FlashSystems as well as deleted there and it's fabulously likely that nicely named disk units 1 through 40 say are now numbered 1, 5,6,7, 9, 11, 14,15 etc as IBM i picked which drives to mirror to which so that all needs to be cleaned up as well.