Very High Disk Latency ESXI 5.5

   Hi,

we have upgraded one of our ESXI Host to ESXI 5.1 to ESXI 5.5. This host has been working for  few weeks  without any issue. but suddenly we faced huge disk latency on Local attached LUN.ESXI run on HP DL 380p G8 Server. this LUN on direct attached local disk array (HP Smart Array P420i). we tried to troubleshoot using esxtop. please refer below screenshots related to faulty LUN

    ESXTOP HBA mode output : vmhba1 is backed with HP Smart Array P420i . very high DAVG and KAVG

    ESXTOP LUN  mode output : naa.600508b1001 is LUN caused high latency.

    there is no any alert on server Array side. how to troubleshoot this issue ??

    please advice.

    Thanks & Regards,

    Lasantha.