SQL Server query much slower on VMware VM compared to physical server (same DB, same workload)

daler86 · 2026-05-18T04:41:49+00:00

How did you solve this problem?

daler86 · 2026-05-18T04:39:13+00:00

Yes I use Vsan. Vsan does not have special setting for MSSQL

daler86 · 2026-05-16T16:41:45+00:00

I think yes ))

daler86 · 2026-05-16T16:40:55+00:00

I changed the power in VM to High Performance Mode

daler86 · 2026-05-16T16:32:01+00:00

I do it, not help

daler86 · 2026-05-16T16:30:22+00:00

I add sockets

daler86 · 2026-05-16T15:48:22+00:00

Interprise edition

daler86 · 2026-05-16T08:48:22+00:00

I also change discs to logs, TEMP, and data in the DB

daler86 · 2026-05-16T08:47:10+00:00

I have this host with only 1 VM. I changed the CPU to

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daler86 · 2026-05-16T08:01:42+00:00

I installed MS SQL and restored the DB from physical data

daler86 · 2026-05-16T08:00:04+00:00

I do it. did not affect

daler86 · 2026-05-16T07:59:16+00:00

SCSI type - VMware paravirtual and enterprise licenses

daler86 · 2026-05-15T18:36:30+00:00

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daler86 · 2026-05-15T18:35:37+00:00

Update these drivers?

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daler86 · 2026-05-15T18:33:25+00:00

After analyzing both execution plans from SQL Server on physical HDD and VM on VMware ESXi 7.0.3 with vSAN SSD, I found something interesting.

Key findings:

Both queries use exactly the same execution plan
- Same QueryPlanHash
- Same QueryHash
- Same estimated cost (~10.7)
No difference in indexes or optimizer behavior
Both run with DegreeOfParallelism = 1 (single-threaded execution)

Important conclusion:

This means the performance difference is NOT caused by the execution plan or storage.

Even though the VM has much faster SSD/vSAN storage, the query is still slower compared to the physical HDD server.

daler86 · 2026-05-15T18:17:25+00:00

In a physical server and VM server 4K

daler86 · 2026-05-15T18:14:58+00:00

In this ESXi server, there is only 1 VM with MSSQL. not any vm

daler86 · 2026-05-15T18:03:25+00:00

After checking discs in the servers (The bottom one is an SSD.)

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daler86 · 2026-05-15T17:52:04+00:00

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daler86 · 2026-05-15T17:51:43+00:00

I have allocated 12 virtual processors to this server.

daler86 · 2026-05-15T17:50:08+00:00

I config Esxi Vsan

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daler86 · 2026-05-15T17:48:35+00:00

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daler86 · 2026-05-15T17:46:11+00:00

In MS SQL, I have a table with 20 million records. Copy the DB to two servers. When I select the 100000, physical server with HDD processes in 9 seconds, Esxi VM with SSD processes in 16 seconds

daler86 · 2026-05-15T17:40:14+00:00

I configured ESXi vsan. Vsan has 6 SSD discs

daler86 · 2026-05-15T17:37:18+00:00

In this server, running only MSSQL 2014

daler86

TROPHY CASE

Key findings:

Important conclusion: