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When browsing the datastore on an ESXi server I have noticed that some of the .vmdk files will have a -flat.vmdk. Just wondering why that is. I have tried converting a running machine using “Thin provisioning” and choosing “Flat” file but have not been able create a –flat.vmdk file. Not sure what situation will cause a –flat.vmdk file to get created.


Matt Fitzsimmons

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Flat files are the actual disk data for a virtual disk, the .vmdk file is really just a pointer to either a flat file or RDM. Don't delete them, that would be bad. If you're interested open up a .vmdk file with a text editor.

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I did notice that in the datastore browser that only certain VMs have the -flat.vmdk file as well as the <name>.vmdk which is the descriptor file. All of the VMs that I have created today do not have the -flat.vmdk They just have a <name>.vmdk that is the actual virtual disk. – Matt Fitz Feb 23 '11 at 23:43
by default the flat files are hidden. – Chopper3 Feb 24 '11 at 0:46
Ahh, that makes since. So the .vmdk file that I see in the datastore browser is acutally the descriptor file. Any reason some would not be hidden? – Matt Fitz Feb 24 '11 at 14:48
someone been using ssh or scripts? I suspect general 'messing around' :) – Chopper3 Feb 25 '11 at 19:16

I believe only thick-provisioned VMs will have '-flat' files.

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Not on my ESX(i) 4.1 system, thin provisioned disks get a -flat too. – Iain Feb 25 '11 at 16:58
agreed, it's RDMs that don't have -thin's – Chopper3 Feb 25 '11 at 19:15

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