vscsistats tool for troubleshooting the virtual machines storage performance

vscsistats  tool for troubleshooting the virtual machines storage performance

 esxtop is a great tool for performance analysis of all types.  However,  with only latency and throughput statistics, esxtop will not provide the  full picture of the storage profile.  Furthermore, esxtop only provides  latency numbers for Fiber Channel and iSCSI storage.  Latency analysis  of NFS traffic is not possible with esxtop.

vscsistats is a great tool used for troubleshooting virtual machines storage performance. The tool works at the virtual SCSI device level in the kernel. This means that you can use it for virtual machines on local disk, fiber channel, iSCSI or NFS.

1 Step open SSH to ESXi host list of all VMs running on host with example output to get VM world ID:

#vscsiStats -l

Virtual Machine worldGroupID: 966699, Virtual Machine Display Name: io1, Virtual Machine Config File: /vmfs/volumes/datastore1/io1/io1.vmx,

 

2. Start SCSI stats tracing in memory for specific VM (in this case worldGroupID: 966699):

#vscsiStats -t -s -w 966699

 

3. (optional) to Monitor live IO latency and IO size or outstandingIOs for specific vmdk:

# vscsiStats -p ioLength -c -w 106037030 -i 8481

# vscsiStats -p latency -c -w 106037030 -i 8481

# vscsiStats -p outstandingIOs -c -w 106037030 -i 8481

 

4. Once throughput issue been captured save/dump data from memory to csv file for export :

 #vscsiStats -p all -c -w <worldID> > /tmp/vmstats-<vmname>.csv

 

5. Stop collection :

#vscsiStats -x

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