ESXTOP Flashcards

by admin

ESXTOP is a great tool for troubleshooting performance issues, but there are a lot of different metrics that you need to be aware of in order to use it effectively. I’ve previously written about esxtop metrics, but have been looking for a good way to help them sink in! With this in mind, I’ve created some interactive flashcards covering many of the most useful metrics for troubleshooting performance, as a way to commit them to memory.


  • %RDY
    Threshold = 10. Generally high with overprovisioning of vCPUs or excessive usage of vSMP
  • %SYS
    Threshold = 20. The percentage of time used for system services for the CPU world. A high value indicates high I/O
  • %WAIT
    The percentage of time a world has spent in the wait state. The %WAIT is the total wait time which includes %IDLE and I/O wait time.
  • %USED
    Tells you how much time the virtual machine spent executing CPU cycles on the physical CPU
  • %CSTP
    Threshold = 3. High when excessive use of vSMP. Look at reducing vCPU count on VM
  • %IDLE
    The percentage of time a world is in idle loop.
  • %MLMTD
    Threshold = 0. Percentage of time the world was ready to run but was deliberately not scheduled as it would have violated CPU limits
  • %RUN
    Percentage of total time scheduled for the world to run. %USED = %RUN + %SYS – %OVRLP. High value means the VM is using a lot of CPU resource
  • %SWPWT
    The percentage of time the world is waiting for the VMkernel swapping memory.
  • %OVRLP
    Percentage of time spent by system services on other worlds. A high value indicates the host is experiencing high I/O

ESXTOP Memory Metrics

  • %ACTV
    The percentage of active guest memory
    The amount of memory that has been granted to the world group
  • SWR/s
    Threshold = 1. Value greater than 0 means host is reading from swap
    Threshold = 1. If greater than 0 then the host is having to reclaim memory using the balloon driver
    The value, in MB, of the configured guest memory
  • SWW/s
    Threshold = 1. Value greater than 0 means host is writing to swap
    Threshold = 1. Value greater than 0 means host has swapped memory pages

ESXTOP Network Metrics

  • MbRX/s
    Megabit Received
  • MbTX/s
    Megabit Transmitted
  • %DRPTX
    Threshold = 1. Indicates dropped packets transmitted, likely very high network utilisation
  • %DRPRX
    Threshold = 1. Indicates dropped received packets, likely very high network utilisation

ESXTOP Disk Metrics

  • GAVG
    Threshold = 25. GAVG is the sum of DAVG + KAVG
  • CONS/s
    Threshold = 20. SCSI reservation conflicts per second. A high value is an indication of performance degradation
  • QUED
    Threshold = 1. Indication that there are disk queuing issues on the host
  • KAVG
    Threshold = 2. Disk latency caused by the VMkernel.
  • DAVG
    Threshold = 25. Disk latency, likely caused by the storage array
  • CMDS/s
    Total amount of commands per second, which includes IOPS and other SCSI commands (e.g. reservations and locks). CMDS/s = IOPS
  • ABRTS/s
    Threshold = 1. Aborts issued by guest. Indication that the storage is non responding
  • RESETS/s
    Threshold = 1. Number of commands reset per second
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