Provided are a method, system, and program for maintaining consistency
when mirroring data using different copy technologies. Update groups
having updates to primary storage locations are formed using a first copy
technology. The updates in the update groups are copied to secondary
storage locations. Update groups having updates to primary storage
locations are formed using a second copy technology, wherein the updates
in the update groups are copied to secondary storage locations.
Indication is made in a data structure of a time of an update in response
to including the update in one of the update groups formed using the
first copy technology. Indication is also made in the data structure of a
time of the update group formed using the second copy technology.