Performance Head to Head (vDisk Sharding) >> AOS 5.20x vs 6.1x

“Be a yardstick of quality. Some people aren’t used to an environment where excellence is expected.”

 Steve Jobs 

For many Nutanix customers quality has become expected and, unlike hardware, software continues to appreciate as we upgrade. The following is a testament to that focus on quality mentioned by Steve Jobs above. We should be constantly outdoing ourselves with each new AOS release and 6.1 has done that well.

AOS 6.1 is the latest STS (short term support) release that has just GA’d from Nutanix. Below I am using the free Nutanix tool “X-Ray“. X-Ray is essentially a performance/resiliency testing tool with a nice GUI and automation/reporting capabilities built on top of the open-sourced FIO performance load tester.

The Cluster Setup

For this bake off I am using a 4 node cluster running 5.20.3 LTS. Then performed an AOS upgrade to 6.1 and ran the same tests. This performance test will show the advantages of vDisk Sharding in AOS 6.1x that will greatly improve performance for scale-up databases who have vDisks larger than 500GB. You will see in 5.20.3 which does not have the new vDisk Sharding feature that those larger single vDisk setups will not show a perf boost but as you move to 6.1x those larger database vDisks will see a nice boost. 😎

X-Ray Version4.2.4

AOS 5.20.3/AHV Nutanix 20201105.2244 (4 node)

AOS 6.1/AHV Nutanix 20201105.30142 (4 node)

The Test

This X-ray test is a default test baked in called the “AOS vDisk Sharding Performance“. This test (as shown below) will show the value gained by the new feature in 6.1x called vDisk Sharding which will greatly improve scale-up database performance as mentioned earlier.

The Results

No Sharding Enabled

vDisk Sharding Enabled


So, some may be asking “why did you run this test on 5.20.3 when the test literally states to use 6.1 to see vDisk Sharding?” The purpose was to show that prior to 6.1 when we scale up large disks for legacy apps or scale-up databases we would see no improvement passing the 500GB mark. Moving on to 6.1 we see a MASSIVE increase in performance with larger than 500GB vDisks. From AOS version 5.20.3 with over 500GB vDisks we saw 143.56k IOPs and with 6.1 with over 500GB vDisks we see 369.58k IOPs which is a 157% INCREASE! Latency also decreased by 61% due to multi threading the IO to the single vdisk versus forcing all IO to a single thread.

As a bonus you may have also noticed that even with smaller vDisks where vDisk Sharding would not be enabled AOS 6.1 still showed improved IOPs and lower latency. This is due to the constant focus on performance by Nutanix as they further enhance the IO path.

For more information on vDisk Sharding check out the Book of AOS at

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