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LUN Size Versus ctual raw space
https://3parug.com/viewtopic.php?f=18&t=3792
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Author:  kurbennett64 [ Wed Jun 01, 2022 6:52 am ]
Post subject:  LUN Size Versus ctual raw space

Hi all, need some clarification here.

If I create a 16TB Virtual Volume on the 3PAR and export it to a vSphere host, is it really 16TB, or is it smaller or larger on the VMware side?

Reason is the VM side sees a 16TB LUN, if I look at the datastores it shows a 16TB Disk. But when I look at file capacity it shows 17TB of File space. The datastore is only being used by a single Linux Server, and the drive is set for that system at 16TB. No compression or data depup is in play on the systems.

Not sure why there is a discrepancy in size reporting.

Thanks in advance,

Kurt

Author:  MammaGutt [ Thu Jun 02, 2022 1:53 am ]
Post subject:  Re: LUN Size Versus ctual raw space

kurbennett64 wrote:
Hi all, need some clarification here.

If I create a 16TB Virtual Volume on the 3PAR and export it to a vSphere host, is it really 16TB, or is it smaller or larger on the VMware side?

Reason is the VM side sees a 16TB LUN, if I look at the datastores it shows a 16TB Disk. But when I look at file capacity it shows 17TB of File space. The datastore is only being used by a single Linux Server, and the drive is set for that system at 16TB. No compression or data depup is in play on the systems.

Not sure why there is a discrepancy in size reporting.

Thanks in advance,

Kurt


3PAR uses Base2 (GiB, TiB, etc). What is the exact size you're seeing on that 17TB of file space?
16TiB = 17 592 186 044 416 Bytes
16TB = 16 000 000 000 000 Bytes

Author:  kurbennett64 [ Thu Jun 02, 2022 8:22 am ]
Post subject:  Re: LUN Size Versus ctual raw space

The VM side is showing 17,178,521,600 when looking at the file system on the datastore. It is reporting full. My confusion is if the 3PAR VV was created at 16TB why the VM side shows more.

Author:  MammaGutt [ Thu Jun 02, 2022 12:59 pm ]
Post subject:  Re: LUN Size Versus ctual raw space

kurbennett64 wrote:
The VM side is showing 17,178,521,600 when looking at the file system on the datastore. It is reporting full. My confusion is if the 3PAR VV was created at 16TB why the VM side shows more.


17,178,521,600 bytes = 16GiB :)

Maybe you're reading 17,178,512,600 kB? That would be 16TiB.

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