Whether Data ONTAP can execute a vol copy start command depends on how many volume copy operations are already in progress on the storage systems specified in the vol copy start command.
vol copy start vol0 vol1 vol copy start vol2 vol3When these commands are in progress, if you enter additional vol copy start commands, they will fail, because four volume copy operations are already running on the system. Two of the operations are for reading the vol0 and vol2 volumes, and two of the operations are for writing the vol1 and vol3 volumes.
vol copy start systemA:vol0 systemB:vol0vol copy start systemA:vol1 systemB:vol1vol copy start systemA:vol2 systemB:vol2
When these commands are in progress, systemA runs three volume copy operations to read the volumes, and systemB runs three volume copy operations to write the volumes.
An additional vol copy start command to copy between systemA and systemB will succeed because the command adds one more volume copy operation to each storage system.
However, if you enter an additional vol copy start command to copy volumes locally on either systemA or systemB, it will fail. This is because the additional command creates two volume copy operations, one for reading and one for writing, on the storage system that performs the local copying.