topic Re: iSCSI LUN size discrepancy in Windows 2019 in ONTAP Hardware

iSCSI LUN size discrepancy in Windows 2019

THESALOPIAN — Wed, 04 Jun 2025 10:33:11 GMT

I've got a spanned drive in a Windows 2019 server that consists of 6 iSCSI disks that were all meant to be the same size. When I look in disk management Windows is reporting two of the disks to be 16349.35GB and the other 4 to be 16349.87GB in one view and all the same size when viewing the disks as part of the spanned drive. (I've attached a view from disk management to show this)

When I look in system manager or the command line they're all being shown as 15.97TB. I'm getting problems with the two smaller disks reporting errors in Windows and I'm guessing it's down the the difference in size. Does anyone know if it's possible to check the LUN size in GB rather than TB via an SSH session to the storage cluster as I'm trying to nail down where the problem is.

Re: iSCSI LUN size discrepancy in Windows 2019

jcolonfzenpr — Mon, 01 Mar 2021 16:02:04 GMT

you can use the set command to specified how the size is displayed.

set -units GB
set -units MB

[-units {auto|raw|B|KB|MB|GB|TB|PB}] - Data Units
Use this parameter to specify the default units used when reporting data sizes.

Possible values are:

auto - Auto-scale data size for human-readable output
raw - Bytes without unit designation
B - Bytes
KB - Kilobytes
MB - Megabytes
GB - Gigabytes
TB - Terabytes
PB - Petabytes

The default setting is auto.

https://docs.netapp.com/ontap-9/topic/com.netapp.doc.dot-cm-cmpr-930/set.html

Hope this help.

PD: For your specific problem try to check the lun size and lun & igroup ostype

Re: iSCSI LUN size discrepancy in Windows 2019

THESALOPIAN — Mon, 01 Mar 2021 16:34:13 GMT

Thanks, that's just what I was looking for. I checked the size in Gb and they all looked the same size but when I changed the unit to MB then I could see that the two LUNS I have a problem with are 518 MB smaller. I'm hopefully going to re-size the LUNS to match the others in the spanned windows drive.

Thanks for your help.