Difference Between Provision and Used Space

[MrVmware9423]

Dear Team,

can some one please explain me the difference between provision and used disk space in simple words.

regards

Mr VMware

[Alim786]

Hi Mr VMware

Provisioned is how much storage has been allocated.

Used is how much of that allocation is actually being used by the VM.

You may think this should be the same. However, it is only relevant if Thin Provisioning has been used. This is where there will be differences.

[MrVmware9423]

Thanks Alim,

In the below snap I have thin provision datastore size of almost 1TB, Over here "Provisioned Space is 847.34 and Free Space is 630.21. if u say provsion is allocated then if we plus Provision and Free then it is more than 1TB. hence need your assistance on the same.

Regards

Mr VMware

[Alim786]

The above Datastore Capacity Summary is interpreted as follows :-

Capacity is the Total Size.

Provisioned Space is the total size allocated to the VMs.

Free Space is the space not used up by VMs yet.

Therefore, with thin provisioning, you can over provision the amount of space to VMs based upon the Free Space at that time. A VM can be allocated 100GB but be only using 50GB. The remaining unused 50GB is counted as part of the Free Space. This can be seen also by clicking on the "Virtual Machines" tab of the Datastore to see the "Provisioned Space" and "Used Space".

I hope this helps.

[MrVmware9423]

Many Thanks Alim,

You have cleared my confusion . Thanks a ton.

regards

Mr VMware

[NORRISC]

I am at a loss.

  I specifically gave each VM enough space to run the OS and application in our test environment - and now we find that we are running out of space because almost all of the VMs have eaten TWICE the amount I gave them.

  How do I get this space back, when the VMs will not let me change the HDD size - it is greyed out. :smileysad:

  We are running ESXi 5.5.0 but all the VMs are VM VERSION 8 machines.

Thank You,

C

[khorem]

what if you don't have enough space? and can't do another snapshot?

This is what initially happened. I tried to create a snapshot but after a while it failed, probably because of low storage space (I can't add any additional space either)

Went to snapshot manager to see if there are any snapshots available... none

went to the storage to see if there are any additional vmdk files I saw one with provisioned.... im assuming thats the corrupted snapshot thats causing the issue...

Q: if that is the file that needs to be removed, How can i remove it; Is there a manual way of removing it? I can't create another snapshot due to shortage of space, I can not increase the storage size. please advise. Thanks.

[AnaghB]

Hello  ,

 

The screenshot that you have uploaded mentions that there are 2 HDD in the Folder.

1. VM_Name.vmdk

2. VM_Name_1.vmdk.

These are 2 different HDD which might contain similar or different Data. Please check before deleting.

 

[Port2Tech]

Good day all,

I realize this topic is old but I am new to dealing with the care and feeding of VMs and the Dell ESXi systems.

I have added more storage and created a new datastore. After the datastore was creates, I looked at the details of the store and noticed that 988MB of space was set as provisioned. After reading the posts in this thread, I am starting to understand but I have not, to my knowledge, actually provisioned any storage to the VMs currently running on the system. So I am trying to understand why the report is showing that 988MB have been used. I do have thin provisioning active, as I copied the settings from the existing datastores on the system.
Guessing that I missed a setting when creating this new datastore?

Thank you in advance!

[NORRISC]

Additional Information -  I removed all the SNAPSHOTS (2 of them) from this VM as well, and now with the VM shut down, the HDD size option is no longer greyed out...but it will not allow me to change the size.  I have also change the size of the disc in the OS itself.  It has been changed from 200gb to 120gb - shows in the OS 80GB of unallocated space.

Why can I not release that space by to my VM pool for use in other VMs that I need to increase their HDD sizes?

Thanks,

C

[AnaghB]

Hello ,

Vmware prohibits to reduce the size of the disk. This can cause to Data loss. The Windows OS formats the disk with NTFS Filesystem which has Random Writes. So if we write the data then the data is scattered on the disk and is not in sequential order. When you reduce the disk from 200GB to 120 GB then the 80GB sectors that are reduces might contain frangments of data which gets deleted causing data loss.

From Vmware Best Practice if you want to reduce the size of the disk then please use Vmware Convertor or create a new HDD of 120GB, copy the data from 200GB Drive to 120GB Drive within the Guest OS and delete the 200GB post confirming that all data is intact.

 

[AnaghB]

Hello  ,

 

The assigned space is the size of the disk that you had specified while creation of the VM. I see in the screenshot that you had created Thick Provision disk of 200GB. Thick provision means that even if the disk is empty within the guest OS the whole space is allocated to the disk from Datastore so it will show as 200GB used.

For the usage of above 200 GB. When we Power ON the VM there is a .swap file created for memory swapping. The size of the file is equal to the Memory/RAM allocated to the VM. 

So if the Thick disk is 200 GB and you have assigned 24GB of RAM to the VM then the total usage of that VM on Datastore is 224GB.

When you Power OFF the VM the .swap file is deleted and the usage comes back to 200GB of HDD.

Please let me know if there are any queries around this. We can discuss this at length.