Techniques are provided for performing a copy operation. An instant
virtual copy operation is issued from a first portion of data to a
primary mirroring portion of data, wherein the primary mirroring portion
of data corresponds to a secondary mirroring portion of data, and wherein
the primary mirroring portion of data and the secondary mirroring portion
of data are in a mirroring relationship. The mirroring relationship is
transitioned to a duplex pending state in response to determining that
the mirroring relationship is in a full duplex state. When the mirroring
relationship is in a duplex pending state, each block of data involved in
the instant virtual copy operation is transferred from the primary
mirroring portion of data to the secondary mirroring portion of data.