Data Backup and Recovery

Lun Offline


Good morning,

I have a storage 3210. I use SQL Server 2008 to access the LUNs. The volume has 50 GB and 40 GB lun is not enabled "Allow to volume to grow automatically" and also is not enabled "Auto delete snapshot automatically."

When the lun is full, the lun is offline. I wonder if the storage is a problem?

Or if you have any configuration for the lun does not go offline when it becomes full??




Hi Erico,

Depends on the LUN and what its doing.

If the volume is full then this will then take the LUN off line to ensure that your Windows environment doesn’t try to write to a LUN that no longer has space in its supporting volume.

The LUN itself can also fill up dependent on the type of things going on…If there is a lot of adding and deleting files then this can take up LUN space, even though Windows thinks there is plenty of space…

Space reclamation frees that space up…but does create a big backup next time around.

But start with checking available volume space and go from there…

Paul Stringfellow

DDI:0151 221 3519

Tel: 0151 220 5552


Twitter @techstringy

Mount Points I'm using Windows Server 2008. If I have a volume and lun. When one gets full the lun lun is offline. It is possible that the mount point is causing this problem goes offline the lun??

Don’t think the mount point is the problem if the NetApp volume fills it will offline the LUN.

If you look at your volume information how much free space do you have?

The lun is full. But this setting to leave the lun offline is standard or it is possible to change? Because with the lun as a mount point without being a lun is not offline.

The reason the LUN goes off line is what can happen is that Windows can think the LUN still has space available to it, however the LUN at the backend can actually be full because of things like data been deleted etc…so although Windows thinks that data has gone…the filer at the back end just sees the deletion as block changes in the LUN.

You need to do a space reclamation on the LUN to get that space back…always useful if the data on the LUN changes on a regular basis.

So there is no option that I’m aware of to stop a LUN going off line…it does that to protect itself from and OS trying to commit data when no space exists in the LUN or the NetApp volume that it is in.

Things like SQL can cause this, especially if the lun has transaction logs on it…as they can change a lot.

Thanks for replay.

It has a command that would make this "space reclamation on the LUN to get that space back"?

If you have SnapDrive installed on your server, hopefully you have, its an option in snapdrive, you’ll see it down the left hand panel.

If you’re not using SnapDrive on your windows server, I’d suggest well worth getting a copy from the NOW site and installing it on the Windows server, it will give you much better integration between the NetApp and Windows environment.


“lun as a mount point without being a lun” – do you mean network share?

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