While migrating data between two arrays using sVmotion with Hardware Accelerated Move (XCOPY) enabled user may see data transfer rate between the arrays is slow compared to when XCOPY is disabled.
The slowness depends on amount of data being migrated and connection between the arrays , however the time to migrate data for XCOPY enabled and disabled case differs.
Currently there is no resolution.
Workaround:
As work around customer can disable Hardware Accelerated Move (XCOPY) to improve the data migration performance.
To disable XCOPY on ESXi host please follow steps mentioned in KB - Disabling Hardware Accelerated Move (XCOPY) in ESXi
Please note: Please disable XCOPY on all hosts that is involved in migration.