VNX 5200 File server CIFS data disappeared

We have VNX 5200 unified and on last Thursday 2-NOV-2017 we planned to power down the VNX using the planned power down procedure in the VNX system operation document and on Wednesday 8-Nov-2017 we have powered it up  using the powerup procedure ,

but the users after that not able to access the file server, we checked the GUI and found the file server data is disappeared and the used is 0% while it was there around 85% of data before the poweroff operation .