Open System (Fixed block) devices can be specified in a FlashCopy® relationship as long as a CKD volume is available (online with a UCB) and is located in the same cluster of the subsystem as the Open System device specified as the source volume. When open system volumes are managed by z/OS® using FlashCopy commands, avoid using other device management methods, such as the TotalStorage ESS Copy Services Web interface, that might result in a conflict.