Avoiding RECON data set space problems

Allocate the RECON data sets with different amounts of space so that if one becomes full, the system can continue using the other RECON data set while you provide a replacement. Allocate secondary extents for the RECON data set when you define space for it.

If one RECON data set becomes full during online operation, IMS deallocates it. DBRC responds by copying and reorganizing the good RECON data set to a spare RECON data set, if one is available. If no spare RECON data set is available, the system runs in single-RECON mode.

When all active subsystems have deallocated the failing RECON data set, you can delete and redefine it offline using AMS. See Replacing a discarded RECON data set for information on replacing a discarded RECON data set. If you are in single mode, and a spare RECON data set is available, the next time DBRC accesses the RECON data set, it automatically enters dual-RECON mode. You do not have to enter the CHANGE.RECON command with the DUAL or REPLACE option.