High latency in accessing LUN

Hi

I have VNX5500 with around 160TB of usable space with 75% utilisation. For the last 2 months we are observing high latency for some of the LUNs assigned to ESXi hosts having our SAP cluster. There is a sudden hike in LUN latency between 3-4AM, and because of the high latency cluster is getting failed quite frequently. Can anybody help me in identifying the LUN and host causing this high latency and the forced flush observed during this period.

Thanks in advance for the help.

Regards,

Tiju Kumar