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In order to maintain consistency of SRDF pairs, Dell implements synchronous XCOPY for any SRDF target device using SRDF/S or SRDF/Metro. The performance of the synchronous implementation is more akin to the VMware software copy than the Dell’ asynchronous implementation for SRDF/A or non-SRDF targets. As such, while Dell synchronous copy generally outpaces VMware host copy, the improvement does not mirror the improvements for asynchronous copy. It is more desirable to offload the copy to the array to free the host and network resources for more important activities. If the time to complete an XCOPY task is more critical than the resources saved on the host, Dell can disable XCOPY for SRDF devices on the array.
Note: For more detail on XCOPY performance considerations, see Dell KB 533648.