To issue the command RCLSTG, we need the system in restricted state, the reclaimed objects will be in the Library ” QRECOVERY ”
To execute the reclaim storage command your machine will need to be in “restricted state” – that means that all the subsystems apart from the controlling subsystem will need to be stopped.
You should either sign on to your system console (if you have one) or use your HMC (if you have one) – alternatively you can transfer your interactive job into the controlling subsystem (system value QCTLSBSD) – for example to the QCTL subsystem :-
Once your interactive job is in the controlling subsystem you can stop all your subsystems using the ENDSYS command. You should receive a message indicating that the ENDSYS has completed. Now you can run your RCLSTG command.
Once the RCLSTG command has completed, you can restart the subsystems manually or re-IPL the system to get everything started automatically (assuming your system has been setup to do this in the QSTRUPPGM).
I recommend you make an Entire System Save before the Reclaim Storage. Keep in mind that the “complete” RCLSTG could take more than 2 hours (it depends on your dasd, ocupation, last time your run it, etc). I usually when no users are in the system and when it does not affect the production (in my business ATM activity is a must).