How can I reclaim the Flexvol space

[9410]

Hi I have a probram in Fas2020,

First I create a 1.3TB flex volume，and map a lun the a server which running windows 2003 R2，

When I create the 1.3TB LUN,

I don't select the space reserved check bok,

and the volume cancel all the snapshot schedule,

One day the user tell me that,

They can't not see the volume in windows,

and I find the DataOntap Syslog Messages,

The Syslog Messages alert say the Volume is full and offline,

and I see the Volume -> Manage show me the avil colume is 0B,

and the  Used colume is 100%,

Then I delete the about 400GB data in Windows,

but when I retun to DataOntap,

the avil colume is still 0B,and the Used colume is still 100%,

and I still can't save any file to the volume in the windows,

I ask some people,

but their answers are the same,

is tell me delete the snapshot,

but I don't have any snapshot!

I don't know why,

Can any one help me to fix this problem?

Thank!

[adamfox · Accepted solution]

If your LUN is the same size as your volume even with no space reservations and no snapshots the ONTAP  FlexVol will be full because the LUN is using up the space in the volume.  This is ok as long as you don't want to take a snapshot of that volume.  The Windows host should see the free space inside the LUN so the host should be able to write inside that LUN even though the FlexVol says it has no space.

Now, starting with SnapDrive 6.1 for WIndows (only for Windows), if you thin provision your volume, SnapDrive reclaim blocks for the volume so that you are only consuming the used space in the volume that is being used in the LUN.

Hope this helps.

[9410]

Hi Adamfox：

If i use the snapdrive,

Will I lost any data in the LUN?

[adamfox]

I don't believe so.  If you aren't sure how to work with SnapDrive and your existing LUNs, I'd contact Tech Support.

[radek_kubka]

Hi and welcome to the forums!

It looks like the fractional reserve may kicked in, indeed - but this could only happen if you have at least one snapshot of that volume (see Chris's blog post for a very thorough explanation: http://communities.netapp.com/groups/chris-kranz-hardware-pro/blog/2009/03/05/fractional-reservation--lun-overwrite)

Other than that, you should never set the volume size & the LUN size to the same value - any volume should always have some free space in it.

One of the ways you can get out of the trouble, is to increase the size of the volume & also you may consider thin provisioning, i.e. setting volume space guarantee to none (this plus some other settings, like snap autodelete are explained in aforementioned blog post).

Also bear in mind ONTAP is (under normal circumstances) not aware of data being deleted within a LUN.

Regards,
Radek

[9410]

Hi mbbmbhj：

If I don't have any aditional disk to increase,

Is any other way to reclaim the flexvol space?

[jb2cool01]

Oops, double post

[jb2cool01]

Surely the 1.3Tb LUN is simply using all the space. Space reservation would reserve an additional 1.3Tb of space (If it was available) to guarantee that there is enough space to change all blocks.