Slow creation of disks in v15.1.0 for new VM

[munrobasher]

Anyone else noticed that it seems to take a long time creating the disk for a new VM? This step used to be pretty fast - or at least I don't recall sitting watching it but it took about 30 seconds to created the disk on a new VM based on an SSD:

And during that time, it's thrashing the SSD:

[munrobasher]

Later - just created another VM and it's taken ages to create the disk again. Managed to catch Resource Monitor this time:

That write speed is pretty good. It's to a SSD but only connected via SATA-2.

Ahh... I've just done another test and I've discovered the problem... when creating a new VM, it's creating a 8GB VMDK file:

This is before the VM is booted. It took 3 minutes to create the VM and write this 8GB disk which fits in with the write speed of ~48MB/s.

So the title of this post is wrong - it's not the write speed that's the problem, it's why Workstation creating a 8GB empty disk at the start? With thin provisioning, it should be very small before the VM is booed.

[a_p_]

What's the virtual disk's provisioned size?

That file .vmdk file should only contain metadata (i.e. header. grain directories/tables, and a lot of zeroed out space), so please compress/zip it, and attach the .zip archive it to a reply post.

Anderé

[munrobasher]

Further information - this "problem" only occurs when creating Windows 10 VMs. Just created a test Ubuntu VM and as expected, the VMDK disk is tiny at 2.56MB:

[munrobasher]

>What's the virtual disk's provisioned size?

100GB in a single file.

>That file .vmdk file should only contain metadata (i.e. header. grain directories/tables, and a lot of zeroed out space), so please compress/zip it, and attach the .zip archive it to a reply post.

Will do - I've just deleted it so will have to re-create. I mounted the VMDK on another VM just to have a peek. As expected, it mounted as an uninitialised drive.

I wondered if it was because I was created a test VM with Windows 10 May 2019 edition but the same occurs with the Oct 2018 edition.

[munrobasher]

Attached is the hex dump of the first 128Kb of the VMDK. The following pattern is repeated many times:

[a_p_]

The attached file doesn't look like a monolithic virtual disk (.vmdk) file, although the portion that you've pasted shows a part of the grain directory!?

André

[munrobasher]

It wasn't - it was a quick hex dump of the first 128MB. The ZIP of the VMDK is attached. It's gone down from 8GB to 9.91MB which shows it's got a lot of repeated data in there.

[bonnie201110141 · Accepted solution]

VMware Workstation will pre-allocate 8GB disk space for Windows 7 or above VM, even though it is is thin-provisioned. It is to improve performance. So I think it is expected.

[a_p_]

Thanks for this information. I wasn't aware of this.

André

[continuum]

Hi Andre

I also had almost forgotten about this .... it was introduced in WS 10 and at that time we could switch it off with

pref.preallocateSparseFront = "FALSE"

Other workaround: use the "I will install later" option of the "create new VM" wizard.

Dont know if it the preferences.ini entry still works with WS 15.

See old post from Darius:

Hard Disk Space Allocation while Creating a new VM in Workstation 10

[continuum]

@Yifen Wei

> even though it is is thin-provisioned.

Please avoid this terminology. Please use sparse provisioned.

Thin-provisioned should be used for ESXi only as it confuses users who are not aware of the differences.

Thank you

Ulli

[bonnie201110141]

Thanks continuum for your remind! I did not realize that 🙂

[munrobasher]

I wasn't aware of it either... surprised it's been there since v10. But thanks, least we know why it takes a bit longer to create a Windows 10 VM compared to other OS.

>Other workaround: use the "I will install later" option of the "create new VM" wizard.

Ahh.... that explains it. I had historically avoided the "Installer disk image" option as in early versions I had quirks with it. So I always picked "I will install the operating system later" option. Except now that the "Installer disk image file" option appears to work fine, I selected that.