Poor host performance when any VM has a snapshot.

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Host: MacPro6,1, latest efi and smc firmwares.  12cores, 24logical processsors, 32gb of ram, 1x1tb SSD.

ESXi: 6.5u1, October updates.

Guests: Total 4: All macOS 10.12.6 or 10.13 w/ 2-4cores and 5gb of memory.  100GB thick provisioned, lazy zeroed vmdks.

If I take a snapshot of any of the vm's, when the system with the snapshot is in use, the rest of the systems constantly(every few seconds for multiple seconds) become unresponsive. The host becomes unresponsive at the terminal via SSH and in the web interface as well.

This system worked fine performance wise for the last three years using ESXi6.0.  We moved to 6.5 last week to support the latest macOS release, after which this performance issue appeared.

Does this issue ring any bells with anyone?  What am I missing?

[admin]

Some common configuration errors can lead to a virtual machine becoming unresponsive, such as while waiting for a resource. Review the virtual machine and host configuration. For more information, see:

• Common ESX/ESXi host configuration issues which can cause virtual machines to become unresponsive (1... 
• Common ESX/ESXi virtual machine configuration issues which can cause virtual machines to become unre...

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Thank you for the feedback.  Unfortunately none of the conditions listed in the articles exist in my configuration.  The articles only mention the VM performance being affected, not the entire host.  When I have a snapshot on a vm the entire host becomes unresponsive for 1-2 seconds at a time, every few seconds, as long as that vm is active.   I can have only 2 vms running, 1 with a snapshot, and it tanks the host responsiveness both in the web interface and ssh keystrokes.  As soon as I delete the snapshot everything is fine.

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Performance is still terrible across the entire host when a single vm has a snapshot with the ESXi 6.5 dec updates, guests running 10.13.3.  A 600mb file copy from one folder on the desktop to another in a different VM takes 5 minutes with long periods of no progress.

[sandu]

Hi,

How many snapshots are we talking about? Having too many snapshots will have a performance impact.

May be you can try the following:

1. Shutdown the problematic VM.

2. Create another VM with a single snapshot and run your tests (Read/write to disk, VM power on etc). If you are seeing a better performance, may be you can consolidate the snapshots.

3. Also have you gone through the performance charts, Disk, CPU, Memory etc?

Thanks

Sandeep