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You Should Know:
1. CPU Constraints
– `esxtop` Command:
esxtop
Press `c` to view CPU metrics.
- Check Load Average:
vmstat -n 1
Ensure load average stays below 1.00.
- Check %READY Time:
esxtop -> CPU view -> %RDY
Keep under 5%.
- Adjust CPU Allocation:
vim-cmd vmsvc/getallvms # List VMs vim-cmd vmsvc/reconfigure <VMID> --numvcpus <new_count>
2. Memory Overcommitment
- Monitor Memory:
esxtop -> Memory view -> MCTLSZ (Ballooning), SWCUR (Swapping)
- Adjust Memory:
vim-cmd vmsvc/reconfigure <VMID> --mem <new_memory_in_MB>
3. Storage Latency
- Check DAVG (Device Latency):
esxtop -> Disk view -> DAVG/cmd
Keep below 10ms.
- Optimize Storage:
esxcli storage core device list # List storage devices esxcli storage nmp device list # Check multipathing
4. Network Latency
- Test Network Speed with
iperf3:iperf3 -s # On server iperf3 -c <server_ip> # On client
- Verify VMXNET3 Adapter:
vim-cmd vmsvc/device.getdevices <VMID> | grep vmxnet3
- Check Network I/O Control:
esxcli network ip connection list
Other Critical Checks
- Update VMware Tools:
vmware-toolbox-cmd -v # Check version
- Remove Snapshots:
vim-cmd vmsvc/snapshot.get <VMID> # List snapshots vim-cmd vmsvc/snapshot.remove <VMID> <SnapshotID>
- Log Monitoring:
cat /var/log/vmware/hostd.log | grep -i error
What Undercode Say
Performance tuning in ESXi requires a systematic approach. Key takeaways:
1. CPU: Monitor `%RDY` and avoid overprovisioning.
- Memory: Ballooning (
MCTLSZ) and swapping (SWCUR) must be minimized. - Storage: High `DAVG` indicates storage bottlenecks—optimize LUNs and drivers.
- Network: Use `iperf3` and `VMXNET3` for optimal throughput.
Expected Output:
– `esxtop` CPU/Memory/Disk metrics.
– `vmstat` for load average.
– `iperf3` network benchmarks.
– `vim-cmd` for VM reconfiguration.
References:
Reported By: Shamseer Siddiqui – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
