To diagnose problems with Storage DRS, you can clear Storage DRS statistics before you manually run Storage DRS.

Important: When you activate the option to clear Storage DRS statistics, statistics are cleared every time Storage DRS runs until you deactivate the option. Always deactivate the option after you diagnose the Storage DRS problem.


Activate Storage DRS for the datastore cluster.


  1. Activate the ClearIoStatsOnSdrsRun option.
    1. Browse to the datastore cluster in the vSphere Client.
    2. Click the Configuration tab and click Services.
    3. Select vSphere DRS and click Edit.
    4. Expand Advanced Options and click Add.
    5. In the Option column, type ClearIoStatsOnSdrsRun.
    6. In the corresponding Value text box, type 1.
    7. Click OK.
  2. Run Storage DRS on the datastore cluster.
    The current Storage DRS statistics for all datastores and virtual disks in all datastore clusters in the vSphere Client inventory are cleared, but no new statistics are collected.
  3. Change the ClearIoStatsOnSdrsRun flag value to 0 to deactivate it.
  4. Run Storage DRS again.
    Storage DRS runs normally. Allow several hours for the new setting to take effect.