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How to deallocate space on a dedupe iscsi device

Posted: Fri Dec 21, 2012 12:19 pm
by zumtest99
Hi,

I created a 4TB dedup iscsi device on a 3.6TB RAID5 partition with the iSCSI SAN Free Edition v6. I thought this will work just fine because of the deduplication effect.
But now I am running into the problem because the iscsi file is almost as big as the partition.
The thing is that the iSCSI device is only filled up to 50% as you can see here https://www.dropbox.com/s/xh2ladeqb3gdi ... 4%20PM.png
But the file is much bigger https://www.dropbox.com/s/s8ykpg65lt3pw ... 7%20PM.png

Then I read here http://www.starwindsoftware.com/forums/ ... t2668.html that with v6 it should be possible to deallocate the unused space but I couldn't find out how.

So is it possible to get back the free space or not?

Re: How to deallocate space on a dedupe iscsi device

Posted: Sun Dec 23, 2012 9:00 pm
by anton (staff)
With the current version of our thin provisioning and deduplication there's no way to do a free space re-claim (pretty much like it's true for Microsoft Storage Spaces - after you've used storage it never gets returned). These are bad news. Good news we'll have a new TP/dedupe engine replacing current implementation and it WILL do free space re-claim (both zero write and SCSI UNMAP supported). Had to release beta in late December but I think we'll be a little bit late so please stay tuned in January 2013.

Re: How to deallocate space on a dedupe iscsi device

Posted: Tue Jan 08, 2013 10:29 pm
by nmatese
Is there any update on this yet? I am quickly running into the same issue.

Thanks,
Nick

Re: How to deallocate space on a dedupe iscsi device

Posted: Wed Jan 09, 2013 10:50 am
by Max (staff)
Not yet.
There is a workaround which can actually save some space for you. For this you'll need an external drive.Since StarWind doesn't handle reclaim - it keeps old data in the spdata files. To overcome this we need to create another Dedupe device and migrate the data to it. This will allow you to get rid of the trash in the spdata file. After that I would recommend to use dynamic partition to keep the dedupe files, so that you can extend the partition when you start running out of space. (It's just a precaution measure, I think until that time our R&D will release the block reclaim feature)