ESXi 4.1 U1 VMs somehow changing from thin to thick?

[NKKswitches]

I have been creating all my VMs as Thin and I just noticed that some of them have turned into Thick. I haven't cloned or moved any of them. At most I have been using Snapshots on some of them. But I didn't look right after snapshots so I don't know if that is what caused it.

I am worried that they are changing on their own. If it's because of snapshots, is there anyway around that? And if I delete the snapshots will that let them go back to thin?

If any more turn into thick, I am in trouble as I have been using thin to over provision.

Using ESXi 4.1 U1 installable, on a Dell R710 with internal SAS array. Thanks.

[runclear]

Are you going off what the GUI reports? if so i believe there was a old bug for this..

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=102013...

[MauroBonder]

Hi.

Welcome to the Community.

Check this kb --> http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=102013...

Please, don't forget the awarding points for "helpful" and/or "correct" answers. 

Mauro Bonder - Moderator

[NKKswitches]

Before I check this as "answered", I will look into it. I see the article is very recent, this month. I will check for updates as it is the vSphere client reporting thick.

One thing I am unclear about. If a snapshot is always Thick. Does that mean that if you make a snapshot of a 400 GB thin VM that only has 10 GB of data in it, that the Thick snapshot is taking 400 GB on the ESXi datastore?

[NKKswitches]

My vSphere client is currently 4.1.0 build 345043, I did a check for updates and I don't see any newer version. Yet the article listed is from July 9, 2011 and that it affects 4.1.x.... it also states that it has been fixed in the next major release of the vSphere client. Yet it doesn't say what version that is or a link to get it. If my "check for updates" is not showing a newer update, what am I missing?

[a_p_]

IMO the KB article is not quite correct.

This is because the disk chain starts with the snapshot, which is always thick not thin.

Snapshot are always growing (so actually thin provisioned). However, a descriptor file for a thin provisioned virtual disk contains the entry ddb.thinProvisioned = "1" which is not present in a snapshot descriptor file. I assume this is what is checked and due to the missing entry in the snapshot descriptor file the incorrect provisioning type (Thick) is displayed.

Regarding your question about the next major version, I assume this will be version 5.0.

André

[NKKswitches]

So the issue is solved in a future version that is not available? So what do I do in the meantime? Is it simply a display issue and it's really thin? So the "thick" snapshot is still actually thin and the 400 GB VM with only 10 GB of data will only have a 10GB snapshot then right?

So if there is nothing for me to upgrade to, then it seems I need to leave this as unanswered until the new version is released and I can see for myself that the issue is solved.

Or am I missing something.

[a_p_]

"Thin" does not automatically turn into "Thick", so you don't have to worry about this. You have to keep an eye on the datastore usage - especially if it is overcomitted - though, since thin provisioned disks can grow and fill up the disk space.

To verify the disks are thin, you can always take a look at the datastore browser window, where you can see the current and the provisioned size of the virtual disks. RVTools (http://www.robware.net/) can also be helpful in this case.

André

[runclear]

^ good post.. to add - if you have vCenter in your environment - setup some Datastore alerts to warn you of DS usage... We have ours set here to shoot a email to our team when DS % hits 80%...

[NKKswitches]

I only have the free ESXi 4.1 U1 server and the free vSphere client. Under the "Virtual Machines" tab from the home screen, it shows Provisioned Space and Used Space. The confusing part is that it shows 468 GB provisioned (400 GB and 60 GB VM guest partitions), but only 3.15 KB used???? Even if that is the space after the snapshot, I installed apps which certainly takes more than 3.15 KB.

And if I go to the Resource Allocation tab, I can see what datastore the VM drives are on. But it does not show how much actual disk space is used by each VM, nor if they are thick or thin provisioned. It also shows CPU and Memory totals and available. But not Storage totals and available.

And under the Summary tab, it simply shows 2.72 TB capacity, and 284 GB free. While I have over commited the thin disks, I am pretty sure there should be way more free space than this and not sure I trust this info.

Is there another place to look and find out if I still really have Thin VMs and how much free space there really is?

[DSTAVERT]

You are unfortunately faced with a problem. ESXi does not recognize an individual LUN over slightly less than 2 TB. The datastore that was created with the "leftover" space (the .7TB). You would need to migrate the VMs to another location and break up the array into smaller chunks 2TB -512 bytes or smaller. Check to see if the controller has the ability to break up the array into virtual LUNs.

[NKKswitches]

To Dstavert, I read about that when setting up the ESXi server from the start. The single datastore is made of 2, A 1.9 TB and 841.87 GB using extents. Giving me a 2.72 TB cap. I read this is the way to do a datastore over 2 TB.

[a_p_]

As mentioned before, take a look at RVTools. You will find most information you need in this great little tool.

see http://www.robware.net/index.php?option=com_content&view=article&id=18:rvtools&catid=1:category

e.g. the vDatastore tab

André

[DSTAVERT]

Although available extents are not usually recommended but since you are already there I guess that's where you stay.

[NKKswitches]

To A.P., I am now looking at that tool. Thanks. And I don't doubt it's great for info. But if I can, I would like to have some good basic info via the VMware tools. So if there is a way to do it with the vSphere client, that would be nice to know as well.