Thin provisioning doesn't seem to be working correctly

[beekerc]

I am using ESXi 6.5 Update 1.

not overly keen about the web based client interface. I never used 6.0 so i haven't experienced the PC based client, but web based has way more opportunities to skip back screens and lose input than applications.  (side bar $0.02).

I created a VM in the ESXI web client.  I created a disk 40GB in size, but marked it as "Thin Provision".   I looked at WinSCP (I normally keep it running so i can see a folder on the EXSi and my Windows workstation so i can move stuff if i need to) and in the datastore folder, i saw that the <VM name>_flat.vmdk file was 41,943,040 KB big.  I went to the command line via puTTY and navigated to the datastore directory and saw the same thing 42949672960 bytes.  Figuring i did something wrong, i went to the VM properties page and confirmed that the hard drive section said "Thin Provisioned" said "Yes" - which it did.  i then went to the datastore browser and clicked on the vmdk file and it said "0 B". 

what am i missing here??  a thinly provisioned drive means it's only supposed to consume the space on the physical hard drive representative of how much space is used in the virtual disk.  in Hyper-V if you create a fresh Dynamically Expanding disk of whatever size, the initial physical size of the VHD will be on the order of 2 KB per 1GB of virtual disk capacity. 

I went ahead and created a thickly provisioned disk of 40GB size.  in WinSCP and puTTY, it's exactly the same size on the hard drive as the thinly provisioned one.  it does show in the datastore browser that it's 40GB in size (as opposed to 0B), so this differentiation makes sense, but it seems to defeat the purpose of saving physical hard drive space.

One of my biggest concerns is if i have to move vmdk files off the ESXi host, i'd rather move only the consumed amount of disk space and not all the empty space as well.  especially since WinSCP and SFTP add encryption overhead to the transfer so gigabit ethernet feels like 10-BaseT speeds.  (no i do not have vMotion or HA, and yes i do have to move vmdk's on and off the ESXI host fairly regularly).  with Hyper-V, if only 10GB of a 200GB virtual disk is used, then copying the vhd file only requires moving 10GB.  with VMware, it requires moving the entire 200GB.  this doesn't seem right.

unless i'm just not seeing something, Microsoft's Dynamically Expanding drives seems to get the concept of only consuming physical drive space as it's needed, whereas Thin Provisioning is really just an illusion because whether you choose thin or thick, it still consumes the maximum size of the virtual drive on the hard disk.

if i'm wrong, please set me straight.

[beekerc]

One thing to add - i've thought about creating the very small Dynamically Expanding virtual disk in Hyper-V, then using StarWind V2V to convert the .vhd to a thin provisioned .vmdk file, this way i will truly get a minimally sized file.  are there any technical reasons as to why i should or should not do that?

Thanks

[a_p_]

Thin provisioning is done on the file system level (comparable to sparse files in Linux), rather than on the file level.

Thin .vmdk files will show up with their full provisioned size in tools like WinSCP, but you can see the consumed disk space by running e.g. ls -lisa (where the -s option is what's important), which shows the consumed disk space (second column) in addition to the provisioned disk space.

André

[beekerc]

makes more sense now. 

thanks

[Nick_Andreev]

Hi beekerc,

Browse datastore from vSphere, HTML5 or Web Client and open VM folder. For each .vmdk file Provisioned Size column will indicate the total disk space and Size column will indicate consumed space.

Let me know if that makes sense.