ESXTOP overview for Performance Troubleshooting

Products

• VMware vSphere ESXi

Issue/Introduction

• This article provides esxtop quick overview and basic troubleshooting commands
  
  

Environment

• VMware vSphere ESXi 8.X
• VMware vSphere ESXi 7.X

Resolution

1. ESXTOP is one of the very useful tools to troubleshoot different types of resources such as CPU / Memory / Network / Storage.
2. This KB article contains some basic and valuable information how to use ESXTOP to troubleshoot performance issue.
3. ESXTOP Command overview...

• For changing to the different views type:

Network (n) – Fields: A B C D E F K L
Field	Value	Description
%DRPTX	≥ 1	Dropped Packages transmitted/Dropped Packages received. Values larger 0 are a sign for high network utilization
%DRPRX
Used-by/Team-PNIC	N/A	provide information what physical NIC a VM is actually using
CPU (c) – Fields: D F
Field	Value	Description
%USED	N/A	CPU Core cycles used by a VM. High values are an indicator for VMs causing performance problems on ESXi Hosts.
%SWPWT	≥ 5	Counter showing how long a VM has to wait for swapped pages read from disk. A reason for this could be memory overcommitment. Pay attention if %SWPWT is >5!
%MLMTD	≥ 1	Counter showing percentage of time a ready to run vCPU was not scheduled because of a CPU limit setting. Remove the limit for better performance.
%CSTP	≥ 3	This value is interesting if you are using vSMP virtual machines. It shows the percentage of time a ready to run VM has spent in co-deschedule state. If value is >3 decrease the number of vCPUs from the VM concerned.
%RDY	≥ 10	Percentage of time a VM was waiting to be scheduled.If you note values between five and ten percent take care. Possible reasons: too many vCPUs, too many vSMP VMs or a CPU limit setting (check %MLMTD)
Memory (m) – Fields: B D J K Q
Field	Value	Description
MCTLSZ	≥ 1	Amount of guest physical memory (MB) the ESXi Host is reclaiming by balloon driver. A reason for this is memory overcommitment.
ZIP/s	≥ 1	Values larger 0 indicate that the host is actively compressing memory.
UNZIP/s		Values larger 0 indicate that the host is accessing compressed memory. Reason for this behaviour is memory overcommitment.
CACHEUSD	≥ 1	Memory (in MB) compressed by ESXi Host
SWCUR:	≥ 1	Memory (in MB) that has been swapped by VMKernel. Possible cause: memory overcommitment.
SWR/s, SWW/s:	≥ 1	Rate at which the ESXi Host is writing to or reading from swapped memory. Possible cause: memory overcommitment.
Disk (d) – Fields: A B G J
Field	Value	Description
DAVG	≥ 25	Latency at the device driver level Indicator for storage performance troubles
KAVG	≥ 3	Latency caused by VMKernel Possible cause: Queuing (wrong queue depth parameter or wrong failover policy)
GAVG	≥ 25	GAVG = DAVG + KAVG
Resets/s	≥ 1	number of commands reset per second
ABRTS/s	≥ 1	Commands aborted per second If the storage system has not responded within 60 seconds VMs with an Windows Operating System will issue an abort.
NUMA (m) (change to memory view) – Fields: D G
Field	Value	Description
NMN	N/A	Numa Node where the VM is located
N%L	≤ 80	Percentage of VM Memory located at the local NUMA Node. If this value is less than 80 Percent the VM will experience performance issues
NLMEM	N/A	VM Memory (in MB) located at local Node
NRMEM	N/A	VM Memory (in MB) located at remote Node