ONTAP Discussions

Lun and volume free space difference

cit_fas2050

Dear all,

 

My system is FAS 2552 in c-mode 8.3.2

For my vSphere cluster I have 4 1TB LUNs in VMFS. Each LUN is in one think provisionning volume of 1.2TB. Deduplication is enable

 

I don't understand why I have more free space on my LUNs instead of my volumes ?

For example : my LUN1 have 380GB free space but volume have only 151GB free space. This night I move many data in a virtual machine (approximately 200GB), my VMs are in think provisionning. This morning my datastore is down Smiley Mad  When I see the free space, the LUN is ok but my volume is full. How it is possible my volume was full while my LUN is smaller than my volume ans not full ?

 

Thanks for your explanations

 

 

Regards

 

 

1 ACCEPTED SOLUTION

Mjizzini

LUN is a large file inside the volume. You can have multiple LUNs in the same volume.

Total Volume size= data space +  Snapshot reserve .

 

Note that, if the snapshot copies grow to be bigger than the Snapshot reserve size, the volume data space will be used for extra snapshot space.

 

 

Configuring volumes to automatically grow and shrink their size 

https://docs.netapp.com/ontap-9/topic/com.netapp.doc.dot-cm-vsmg/GUID-ECE453FE-D158-4BDA-9851-6B8780474E11.html

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7 REPLIES 7

nicholsongc

I'm having difficulty following the wording of your question.  Are you trying to say that these are THIN or THICK provisioned volumes?

 

Also - are you going by the vCenter/Host reporting of LUN space or by Netapp/Sys Mgr?  I've learned that you should ALWAYS go by the HOST's perspective when it comes to determining the utilization of LUNs... this is true of ANY storage vendor.

cit_fas2050

Sorry for my English Smiley Frustrated

My volumes are thin. The problem is not the free space on my LUN but on my volume. How can I no longer have free space in my volume while on my LUN there are still ? My LUN is smaller than my volume...

The view is in NetApp Data Ontap

 

Regards

cit_fas2050

Nobody to answer me ? Man Sad

alexj

Sounds to me like you have snapshots enabled without knowing it and/or a lack of fractional reserve. You need to leave enough space free in the volume to account for overwrites and snapshots.

 

Fractional reserve info: https://library.netapp.com/ecmdocs/ECMP1393894/html/GUID-596042AF-8E9C-4187-969C-633DFDD5A936.html

mduraphe72

What is standard difference between Total LUN Space and Total Volume Space?

Why there should be space difference  between Volume and LUN? What is purpose?

 

Mjizzini

LUN is a large file inside the volume. You can have multiple LUNs in the sam volume.

Total Volume size= data space +  space used by Snapshot copies or the Snapshot reserve (whichever is greater).

 

 

Configuring volumes to automatically grow and shrink their size 

https://docs.netapp.com/ontap-9/topic/com.netapp.doc.dot-cm-vsmg/GUID-ECE453FE-D158-4BDA-9851-6B8780474E11.html

 

Mjizzini

LUN is a large file inside the volume. You can have multiple LUNs in the same volume.

Total Volume size= data space +  Snapshot reserve .

 

Note that, if the snapshot copies grow to be bigger than the Snapshot reserve size, the volume data space will be used for extra snapshot space.

 

 

Configuring volumes to automatically grow and shrink their size 

https://docs.netapp.com/ontap-9/topic/com.netapp.doc.dot-cm-vsmg/GUID-ECE453FE-D158-4BDA-9851-6B8780474E11.html

View solution in original post

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