Synology thinks it is using 8TB more than it really is!

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SoriceConsulting
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Synology thinks it is using 8TB more than it really is!

Unread post by SoriceConsulting » Thu Aug 23, 2018 1:18 pm

On my DS1815, I have 1 Volume, 1 Shared Folder and 1 iSCSI LUN

Have (4) 9.1TB drives and am using Hybrid RAID (SHR) with 1 disk fault tolerance

I don't use Cloud Station or anything else that would create versions or any type of hidden storage.

Recycled bins have all been emptied

Synology reports that my Shared Folder is 200GB (which is correct)

I setup my LUN as thin-provisioned with a max size 26 TB

Synology reports that my LUN is using 22.26 TB, with 3.92 TB free

However, in Windows, my iSCSI drive reports (correctly) that it is has 11.8 TB free out of 25.3 TB (not sure why it reports 25.3 and not 26).

So I've got about an 8 TB discrepancy. How do I get the Synology to recognize the correct used space?

synology_ukman
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by synology_ukman » Thu Aug 23, 2018 2:38 pm

Is this EXT4 or BTRFS?
Possibly reclaim process hasn't run completely whereas Windows marks blocks as deleted.
Have you had a lot of deletes, what is the LUN used for?

SoriceConsulting
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by SoriceConsulting » Thu Aug 23, 2018 4:01 pm

The share is used for Mac users to access store files. The LUN is used as a backup drive, so there are a lot of add/delete actions. I don't recall during LUN setup having thin provisioning without space reclamation as an option, but it does show that in the iSCSI Manager. The LUN shows as btrfs / Thin Provisioning (without space reclamation).

Could that be the cause? Can I turn on reclamation without having to re-create the LUN?

Squozen
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by Squozen » Thu Aug 23, 2018 4:17 pm

No, you need to choose this when creating the LUN.

SoriceConsulting
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by SoriceConsulting » Thu Aug 23, 2018 4:33 pm

So delete/re-create LUN is only option? Seems really drastic. I hope there's a way for DSM to rescan the LUN and release unused space.

synology_ukman
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by synology_ukman » Thu Aug 23, 2018 4:48 pm

SoriceConsulting wrote:
Thu Aug 23, 2018 4:33 pm
So delete/re-create LUN is only option? Seems really drastic. I hope there's a way for DSM to rescan the LUN and release unused space.
Did you read the word "reclamation" and not think it important!?!?

SoriceConsulting
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by SoriceConsulting » Thu Aug 23, 2018 5:11 pm

Looked at my notes. I followed this Synology guide to setup the LUN:
https://www.synology.com/en-us/knowledg ... nology_NAS

No reference to reclamation.

synology_ukman
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Re: Synology thinks it is using 8TB more than it really is!

Unread post by synology_ukman » Fri Aug 24, 2018 12:02 pm

I'm with you, Synology documentation sucks bug time.
Lack of screenshots

darioc
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Re: [Official] Solving storage discrepancies

Unread post by darioc » Fri Sep 07, 2018 9:21 am

I've 2 RS2418RP+ in cluster with 8 disks of 3TB.

On one volume i've some storage reclamation problem.
I've a 2TB volume ->
- 1.8TB on ISCSI LUN
- 200GB on SMB

And now the DSM tell me, " Volume is full" so the LUN is in read only mode. But is not correct.
Here some info :

/dev/drbd-vg1-volume_4 2.0T 1.9T 51G 98% /volume4

LUN on DSM
Image
Volume on DSM
Image
Disk of LUN on Windows server
Image

Someone can point me to resolve this issue ?

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Re: Synology thinks it is using 8TB more than it really is!

Unread post by Squozen » Wed Sep 19, 2018 4:47 pm

Try running SDelete over the Windows drive to force it to zero the blocks.

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