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BlakeTN77
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Comparing Datastore usage to Disk usage on the Server VM: Doesn't Match

I'm a little confused and could use some clarification from someone.

I'm looking at a vm via the vSphere Client and it has an alert telling me that my datastore free space is low. 17.55 GB Free with a total capacity of 134.75 GB. I'm running ESX 4.0 for the host and my VM's are running Server 2008.

I'm confused because when I log in to the VM and check the disk usage in My Computer, it does not reflect what vSphere is telling me. This particlular VM is hardly being used and the disk usage according to windows is very very low. About 20 GB.

Can someone tell me why these numbers aren't matching up? I have other VM's that are in the same situation.

Thanks,

Blake

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a2alpha
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I think you maybe mixing two things up, the vSphere client will only warn about the datastore, the VMFS volume you have created and presented to ESX. You then create a VMDK file for your Virtual Machine to use. If you assign more than 80% of your datastore to a VMDK or multiple VMDKs then the client will report a warning on usage. 80% warning 90% critical even though within each VMDK file you maybe using only a couple of GB.

If you give a bit more detail on the VM and the datastore we should be able to work this out.

Hope this helps,

Dan

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DSTAVERT
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Have you created snapshots. Browse the datastore from the vSphere Client.

-- David -- VMware Communities Moderator
weinstein5
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To add - is the 20 GB how much of the disk in use or how large the disk is? Because, by default, if you have sized the disk to 80 GB even though you are only using 20 GB the file will be 80 GB. Also how much memory is assigned to the VM - when the VM is powered on a per vm vmkernel swap file is created that is equal to the amount of memory assigned to the VM minuse the memory reservation -

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a2alpha
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I think you maybe mixing two things up, the vSphere client will only warn about the datastore, the VMFS volume you have created and presented to ESX. You then create a VMDK file for your Virtual Machine to use. If you assign more than 80% of your datastore to a VMDK or multiple VMDKs then the client will report a warning on usage. 80% warning 90% critical even though within each VMDK file you maybe using only a couple of GB.

If you give a bit more detail on the VM and the datastore we should be able to work this out.

Hope this helps,

Dan

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Phokay
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You can't compare datastore usage to disk usage inside the VMs. It just doesn't match.

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BlakeTN77
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DSTAVERT,

Good question, but I checked and there are no vmsn snapshot files on my datastores. I didn't think I had done any shopshots yet, but it didn't hurt to make sure.

Thanks for the response!

Blake

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BlakeTN77
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This very well may be correct. I'm knew to the world of Vmware so it's a perfectly good assumption that I'm misunderstanding the functionality.

Given the response you gave as well as the one that followed, maybe my question wasn't worded/described in the best way. Let me give this another shot.

I'm not sure what information you need, but I'll continue with the original Datastore that I mentioned before.

Currently, my 'AppSvr_Storage' datastore has a status of "Alert!". The Capacity is showing 134.75 GB and the Free space is showing 17.55 GB. My guess is that there is a threshold setting that is triggering the alert. My question is, how do I interpret this alert? Is this just telling me that I have 150 GB total and I've given this datastore 134 GB which may or may not be used by the VM that is on the datastore?

What other helpful information can I give you?

Thanks so much for the responses!

Blake

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BlakeTN77
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Dan,

I skipped over your response by mistake. I think your explanation describes exactly what I've done. This particular datastore that I mentioned has only one "vmdk" and I gave that vm the bulk of the space (134GB). What you're saying is that vSphere is alerting me because I'm getting close to using up the total storage space that I've allotted to the datastore. In other words, it's telling me that I don't have much to use for snapshots or other vm's. Correct?

Thanks,

Blake

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CCSScot
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Exactly right, as yet, there is no view within the client to report on the usage within your Virtual Machines VMDK file, for that you can use PowerShell etc. What you would probably want to do is create a smaller VMDK for your Virtual Machine unless you need that full space. I normally try and keep the total size of all the VMDKs combined to less than 80% of the datastore size to allow for snapshots etc.

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KamilAzmer
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Blake,

Did you assign your VM using Thin/Thick disk?. If yes, you have to shrink to let .vmdk size is same as VM server size cause if there are activity put and delete the .vmdk will only grow and not decrease. you may use sdelete to shrink and using SVmotion/vconverter to cloning back the disks to actual size.

You may could be check on the datastore and ensure that no other bigger size it's applying to the datastore. you can acknowledge the alarm but it's will still appear cause of alarm trigger.

*Correct me if i'm wrong*

@ -- visit my blog at http://www.azmer.my -- @ virtue your mind @ KamilAzmer
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a2alpha
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You are correct, as CCSScot says. It would be a nice feature for the client to show what is used in the VMs but PowerShell does it well.

Dan

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BlakeTN77
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Thanks for the responses everyone. I think I now correctly understand the functionality of the alerts on the datastores and how it is related and not related to the disk usage on the VM's.

Blake

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