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ve1337
Contributor
Contributor
‎07-27-2017 01:19 PM

Slow disk performance in ESXi but not Windows

Running a Dell R710 with the H700 RAID controller. I have 2 SAS disks connected in RAID 0, and I installed Windows Server 2016 directly on bare metal.

My disk read performance as measured by Crystal Disk Mark was almost 400 mb/s.

Fast forward to ESXi 6.0 installed on bare metal, and Windows Server 2016 running in a VM. No other settings changed. Crystal Disk Mark now indicates a read of 220-250 mb/s. The VM was thick-provisioned with eager zeroing.

What could be wrong with this VM to obtain such poor performance?

Thank you for any help!

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2 Replies
parmarr
VMware Employee
VMware Employee
‎08-01-2017 04:38 AM

Please refer to these documents:

Solution for Disk Performance problems:

https://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vsphere.monitoring.doc_50%2FGUID-E8...

Troubleshooting hosted disk I/O performance problems.

http://kb.vmware.com/kb/1008885

Sincerely, Rahul Parmar VMware Support Moderator
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Nick_Andreev
Expert
Expert
‎08-03-2017 11:01 PM

Just out of curiosity, what are you running on the Windows Server 2016 VM that requires more that 220-250MB/s of read throughput?

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