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We all know how important esxtop is while troubleshooting various vSphere related issues. In this blog I will share the esxtop metrics that you can use while troubleshooting various VAAI primitives. This will help you not only to diagnose VAAI related issues but will also help you measure the performance benefits that VAAI provides.
To demonstrate this I have replicated some scenarios where VAAI is used so that I can capture the esxtop stats.
To access the esxtop metrics, login to the ESXi host using SSH
# press u for disk view
# press f to change fields
# press o for VAAI stats
# press p for VAAI latency stats
# press Enter
Block Zero & Hardware Assisted Locking (ATS)
In this section we will cover the Block Zero VAAI primitive.
Scenario 1: Test BLOCK ZEROING primitive by creating a new Windows 2008 R2 VM with Lazy Zeroed Thick disk.
On monitoring the ZERO statistics I observed that it incremented from 4 to 7007 during the OS reinstallation.
Scenario 2: Test BLOCK ZEROING primitive by adding a new Eager Zeroed Thick virtual disk.
In this scenario I have added a 150 GB Eager Zeroed thick disk and on monitoring esxtop I observed that the ZERO statistics incremented from 7013 to 148020.
Scenario 3: You can either delete a VM or Storage vMotion the VM to a different datastore to demonstrate this.
We will now use the UNMAP primitive from the ESXi shell using the command
# esxcli storage vmfs unmap -l iscsi_2
On monitoring the esxtop I have observed that the DELETE statistics has increased to 52527.
In this section we will cover the Full Copy VAAI primitive.
Scenario 4: Test VAAI FULL COPY primitive, create multiple clones of the same VM.
In this scenario we will initiate a clone of a Windows 2008 R2 VM from vCenter. While monitoring the esxtop I have observed that the CLONE_RD & CLONE_WR statistics incremented. Note that MBC_RD/s & MBC_WR/s is the throughput for Full Copy Read & Write.
Scenario 5: Test VAAI FULL COPY primitive by relocating VM using Storage vMotion.
In this scenario we have migrated the windows VM to another iSCSI LUN that is being managed by the same controller in the same vServer. While monitoring esxtop I have observed that the CLONE_RD (source datasource), CLONE_WR (destination datastore), ATS, ZERO (destination datastore), AAVG (destination datastore) metrics were incremented.
To all VMware & NetApp Administrators go prepared when you walk into the War Room to discuss VAAI related (break/fix & performance) issues, all the best .