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VMWare datastore free space doesn't match the LUN information

[ Edited ]

Hi,

 

This is the background:

 

ESXi 5.5

NetApp Filer

LUN thin provisioned of 700Gb

Datastore thin provisioned of 700Gb

 

The Datastore space reached almost 100% of the space and I'd had to delete a few VM off the datastore and run a few unmap commands on the ESXi server.

 

After the deletion. nothing seems to have changed in terms of free space fromt the vSphere web client and the ESXi SSH session.

 

The output of the dl -h command shows that the datastorage is at 97% of the DS size and you get the same number from the datastorage vSphere view.

 

If I go to System Manager or VSC, the LUN free space is 90%, nonetheless.

 

So, there havent been any change in terms of free storage after the deletion.

 

Could someone tell me where's the space free after the VM machines deletion?

 

Thank you.

Re: VMWare datastore free space doesn't match the LUN information

 

 

TR-3749:

 

DEDUPLICATION CONSIDERATIONS WITH VMFS AND RDM LUNS


Enabling deduplication when provisioning LUNs produces storage savings. However, the default behavior
of a LUN is to reserve an amount of storage equal to the provisioned LUN. This design means that
although the storage array reduces the amount of capacity consumed, any gains made with deduplication
are for the most part unrecognizable, because the space reserved for LUNs is not reduced.
To recognize the storage savings of deduplication with LUNs, you must enable NetApp LUN thin
provisioning.


Note:  Although deduplication reduces the amount of consumed storage, the VMware administrative
team does not see this benefit directly, because its view of the storage is at a LUN layer, and
LUNs always represent their provisioned capacity, whether they are traditional or thin
provisioned. The NetApp Virtual Storage Console (VSC) provides the VI administrator with the
storage use at all layers in the storage stack.


When you enable dedupe on thin-provisioned LUNs, NetApp recommends deploying these LUNs in
FlexVol volumes that are also thin provisioned with a capacity that is 2x the size of the LUN.  When the
LUN is deployed in this manner, the FlexVol volume acts merely as a quota. The storage consumed by
the LUN is reported in FlexVol and its containing aggregate.

Re: VMWare datastore free space doesn't match the LUN information

Hi,

 

I missed to say that dedup is enabled but LUN space reservation and Volume Fractional Reserver are disabled. Snap server is set to 0%.

 

It's a single LUN-Volume.

 

Thank you.

Re: VMWare datastore free space doesn't match the LUN information

Enough free space in aggregate or volume?
Run "df -h", and "df -Ah" on Data ONTAP and check space usage at volume and aggregate level.

Re: VMWare datastore free space doesn't match the LUN information

[ Edited ]

More free space than enough for both, volume and aggregate.

 

Volume      705GB      218GB      486GB      31%

Aggregate  28TB       22TB     6186GB      79%

 

Thank you.

Re: VMWare datastore free space doesn't match the LUN information

[ Edited ]

Any update on this?

 

Thank you.

Re: VMWare datastore free space doesn't match the LUN information

Do you have any snapshots within the DataStore?

 

Ryan

Re: VMWare datastore free space doesn't match the LUN information

Hi,

 

There are a few VM snapshots within that store.

 

But the Datastore free space remains the same even after deleting VMs.

 

There's no Snapshots at the Storage Array level.

 

Thank you.

Re: VMWare datastore free space doesn't match the LUN information

If I go to System Manager or VSC, the LUN free space is 90%, nonetheless.

 

I could only find out "% Used" column in System Manager. Do you mean "% Used" is still 90% even after you have deleted files on DataStore?
Used space at LUN level does not reflect usage of filesystem level. Once actual block is allocated from aggregate, its is counded as "used" and is never freed even after removing files from VMFS. Of cource, this "used" blocks are reused by VMFS.

 Usage statistics at LUN is useless for users and admins, so ignore difference between "df" on ESXi and LUN used space on ONTAP.

Re: VMWare datastore free space doesn't match the LUN information

> I could only find out "% Used" column in System Manager. Do you mean "% Used" is still 90% even after you have deleted files on DataStore?

Yes, that's what I'd like to mean.

> Used space at LUN level does not reflect usage of filesystem level. Once actual block is allocated from aggregate, its is counded as "used" and is never freed even after removing files from VMFS. Of cource, this > "used" blocks are reused by VMFS.
> Usage statistics at LUN is useless for users and admins, so ignore difference between "df" on ESXi and LUN used space on ONTAP.

I deleted the VM machines and afterward, I ran an unmap command over the Datastore to give back the freed blocks to the LUN. I thought that Storage Array takes advantage of VAII and VASA to solve these kind of issues.

 

Thank you.