jentrup
1 Copper

SAN reports volume almost full. Windows reports volume only 50%

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PS6000 v7.0.9

2 host Server 2012 R2 Hyper V Cluster

Volume is 620GB

Group manager reports 525GB in use

Windows Disk managment and Failover cluster manager both report 349GB in use.

Why the difference and where/how to I free up those 175GB?

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Origin3k
3 Cadmium

RE: SAN reports volume almost full. Windows reports volume only 50%

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Because you use iSCSI from an EQL which is a Block storage. The EQL doesnt know that someone from above have data deleted. If a OS deletets data it just marks it as deletet within the allocation table.


Think about when formating a disk and NOT USING quick format. The OS  writes zeros and for the storage it looks like  valid data... but the OS will show it as free space later. For the EQL Volume it means 100% usage.


Windows 2012R2 supports unmap aka space reclamation. It depends on your EQL FW and HIT Version and some other dependencies like Thinpro Volume on the EQL iirc. With that you you can tell the EQL that blocks can be deleted to get some logical space left.

Regards

Joerg

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Origin3k
3 Cadmium

RE: SAN reports volume almost full. Windows reports volume only 50%

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Because you use iSCSI from an EQL which is a Block storage. The EQL doesnt know that someone from above have data deleted. If a OS deletets data it just marks it as deletet within the allocation table.


Think about when formating a disk and NOT USING quick format. The OS  writes zeros and for the storage it looks like  valid data... but the OS will show it as free space later. For the EQL Volume it means 100% usage.


Windows 2012R2 supports unmap aka space reclamation. It depends on your EQL FW and HIT Version and some other dependencies like Thinpro Volume on the EQL iirc. With that you you can tell the EQL that blocks can be deleted to get some logical space left.

Regards

Joerg

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jentrup
1 Copper

RE: SAN reports volume almost full. Windows reports volume only 50%

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Makes sense.

Running HIT 4.9

How do I tell EQL that blocks can be deleted? I found another post but it he was using RHEL

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Origin3k
3 Cadmium

RE: SAN reports volume almost full. Windows reports volume only 50%

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I think that was discussed a couple of times. I only found an older thread about that under http://en.community.dell.com/support-forums/storage/f/3775/t/19592529

We use VMware vSphere and if needed i have to run a command line order. But we dont use ThinPro on EQL Volume level and also use replication so it is out of the game.

Regards
Joerg

DELL-Donald Wi
5 Rhenium

RE: SAN reports volume almost full. Windows reports volume only 50%

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Hello, 

 If you are using HIT/KIT, then you can use the reclaim feature in the ASM GUI.  There is also a CLI utility EQLrethin.exe. 

 FYI:  If the volume is using EQL replication, sync or async, then SCSI UNMAP/Reclaim will not work.  You would have to DISABLE replication, run reclaim, then start replication from scratch. 

 Regards,

Don 

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

jentrup
1 Copper

RE: SAN reports volume almost full. Windows reports volume only 50%

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ASM 4.9 says Rethinning of Cluster Shared Volumes is not supported or am I missing something?

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DELL-Donald Wi
5 Rhenium

RE: SAN reports volume almost full. Windows reports volume only 50%

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Sorry I didn't read closely enough,

 CSV volumes add a layer of complexity.    Only Windows 2012/R2 using VHDX files supports UNMAP. 

https://blog.workinghardinit.work/2012/05/23/trimunmap-support-in-windows-server-2012-hyper-vvhdx/

And that generates the UNMAP command from within the guest OS, so the OS has to recognize that it's a thin 'disk' and send the commands. 

I did some searching and I believe this link might be helpful

https://social.technet.microsoft.com/Forums/windowsserver/en-US/1e221b36-429f-464e-8a4c-7acc6562fd72...

Regards,

Don 

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

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