Aspects of the subject matter described herein relate to sharing volume data via shadow copies. In aspects, an active computer creates a shadow copy of a volume. The shadow copy is exposed to one or more passive computers that may read but not write to the volume. A passive computer may obtain data from the shadow copy by determining whether the data has been written to a differential area and, if so, reading it from the differential area. If the data has not been written to the differential area, the passive computer may obtain it by first reading it from the volume, then re-determining whether it has been written to the differential area, and if so, reading the data from the differential area. Otherwise, the data read from the volume corresponds to the data needed for the shadow copy.