Sebasian
Enthusiast
Enthusiast

high %RDY values

Hi,

Can anybody tell me where to look for the reason for high %RDY. My physical server has two CPUs of 14 Core per socked, total is 28 cores.

Hyper-threading on CPUs is off. ESXI 6.7 U3 is installed on this server and one virtual machine is on this host.

This virtual machine has 26 vCore assigned. On the virtual machine acts as a database server with installed Windows Server 2012 R2 and MsSql Server.

There are no other vm on this ESXI. On the monitoring chart in vCenter and esxtop on esxi console is noted very often high ready and co-stop as on the attached screenshots.

The system (ID 1) and process (ID 37746) of the virtual machine alternately show high ready and co-stop. CPU utilization is above 95% and even 99%

Where to find the reason?

performance1.JPG

performance2.JPG

6 Replies
tayfundeger
Hot Shot
Hot Shot

Can you reduce the amount of CPU on this virtual machine? The% RDY value is caused by an over-given CPU. If there are as many CPUs on the virtual machine that you don't need, you may experience this problem.

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scott28tt
VMware Employee
VMware Employee

High “ready” and “co-stop” when only running a single VM indicates too many vCPUs.


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Sebasian
Enthusiast
Enthusiast

Thank you for your response.

It is a production and strategic virtual machine and unfortunately I cannot restart and stop it from a business point of view.

After disabling HT, I gained significant efficiency of operations on MsSql, which was confirmed by my staff.

From the point of view of Your analysis and colleague in the post below, everything points to oversizing of the virtual machine.

It remains for me to add to the VMware cluster an additional ESXI host with more processor power and more cores.

I will not change on the Virtual machine parameters. After migrating to the new host, I'll be able to see if the problem goes away.

I will inform about the test results for everyone.

For now, what status of post should I choose?

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scott28tt
VMware Employee
VMware Employee

Even with more cores in a new host, the likelihood is that the VM is oversized - plus you may not be able to live migrate the VM from old host to new host.

Taking a clone or building out a replica and doing some load testing away from your production network may be sensible when you do have your new host.

You could mark the first reply as "correct", and re-post in future if the issue remains.


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Although I am a VMware employee I contribute to VMware Communities voluntarily (ie. not in any official capacity)
VMware Training & Certification blog
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IRIX201110141
Champion
Champion

Why is this VM oversized?

It looks like that the VM can easily saturate their 26 vCPUs. Question is why are 2 CPU which are left are not enough for ESXi OS/Management.

For sure there are some thoughts about vNUMA but will that cause high CPU Ready?

Is this %RDY% considered high for a 26vCPU VM?

Was that esxtop screenshot a

esxtop -> V(upper case) -> e <GUID>

one?

Regards,

Joerg

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nascied
Contributor
Contributor

Hi,

Do you have a hot add feature enable in the virtual machine ? if are option is enable, is disabled o vNUMA controle in the virtual machine. I recommend you a read the document below.

https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/solutions/sql-server-on-vmware-bes...

Best regards

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