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bigbluemonster
Contributor
Contributor

Disk Perfomance of clean VM vs Clone VM

Hi

We have ran into an performance issue on a development VM running Windows Server 2003 r2 32bit (Vm Ver7, ESXi 4.1.0), it seems the disk are the issue so we have been doing some performance testing on a number of servers and hosts we have found that even on the same host a Window Server 2003 r2 VM that was cloned from hardware has markedly slower disk performance compared to a cleanly installed VM.

Our testing has been done with clean disks being added to the VMs and formatted via disk part and aligned, in fact a none aligned disk on the clean server runs some 5 times faster during a test written by one of our developers compared to the cloned VM.

Is there anything we can do to the cloned VM? It is currently thick provisioned and the vmware tools installed are the latest and the disk tested are aligned ok. Both servers are running on the same host which is using 4 15k disks in a RAID 10 array

Test results

ReadWriteTest.exe on ETWP TO2 (cloned VM, 2 CPU)

2 minutes 30.82 seconds

2 Minutes 32.43 Seconds

2 Minutes 31.82 Seconds

ReadWriteTest.exe on Test Server (cloned VM, 1 CPU)

36.52 Seconds

36.08 Seconds

37.48 Seconds

The test is a simple exe that creates 10 folder, in each folder it creates another 10 folders and fills each folder with 100 text files with a number in them, the reason this test was created was to simultate 1000s of small files being written to disk. As a guide, I have ran the test on my desktop and it scores 2 minutes 49 seconds.

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6 Replies
bigbluemonster
Contributor
Contributor

The 2nd VM is the clean install VM

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Sreejesh_D
Virtuoso
Virtuoso

Welcome to communities!!.


whats the version of ESX\ ESXi? Are these VMs located in same datastore?

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bigbluemonster
Contributor
Contributor

The version of ESXi is 4.1.0, 348481

The machines I have tested are running on the same host with RAID 10 disks

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Sreejesh_D
Virtuoso
Virtuoso

we've to compare hardware settings of VMs to see the difference which cause this performance lag. To save the time, its good to create a new VM which points to the existing vmdk ( cloned vdmk). By doing this we have a VM with fresh configuration and old data.

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VirtualOSiti
Contributor
Contributor

Are the NTFS Disk Clusters formatted the same on both filesystems? 32K Clusters will improve performance vs. 4K Cluster sizes on NTFS.

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bigbluemonster
Contributor
Contributor

Just copied over the disk from ETWPTO2 (cloned VM) and mounted it on the Clean VM and the performance will not as good as the C drive on the clean VM the disk performance of the cloned disk is still much improved (dropped from 2minutes 30 seconds to 49 seconds) compaired the Virtual hardware both VMs have the follow setup.

ETWPTO2 (cloned VM)

RAM 4096MB

CPU 2

SCSI Controller - LSI Logic Parrallel

Disks - Thick provisioned

All resources set to default

Test Server (Clean VM)

RAM 1024MB

CPU 2

SCSI Controller - LSI Logic Parrallel

Disks - Thick provisioned

All resources set to default

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