Shrinking a ZVOL is not allowed in the User Interface. This can lead to data loss.

[velocity08]

Hi Team

need a little help here if possible :)

we have the following error when trying to grow the iSCSI extent which is connected to a Windows 2016 Svr (VM).

"Shrinking a ZVOL is not allowed in the User Interface. This can lead to data loss."

Originally the config had 8 x Drives
Created an Extent of 6 TiB
connected to Windows 2016
Formatted as REfS
moved some data over
we then added another 8 x drives
The Extent was originally 6 TiB
we then extended it to 9 TiB and this was fine
Moved more data across
Now we would like to extend it to 12 TB

initially we thought it may be snapshots creating the issue so all of those have been removed, still the problem is the same after removeing all the snaps.

i've included a screen shot of the consumed and free capacity.

The issue makes no sense to me as we are extending within the boundaries of available storage and still allowing for more then 20% slack space.

it doesn't matter what number we put in once 9 TiB is changed up only > 10, 11, 12, - 20 TiB the same error presents and wont allow us to extend the Extent.

Specifications:

• FreeNas 13.0
• SuperMicro 2RU 24 bay 2.5" drives
• 128 GB ECC Ram
• 16 x 1.8 TB 7.2k SAS drives (2 x RaidZ2 vDevs with 8 drives per vDev)
• 2 x SSD Zil mirror
• Total usable capacity 21.6 TiB
• 20% slack space = about 4 TiB
• 17 TiB remaining for consumption.
• 9 TiB iSCSI Extent allocated

Wondering if this may be a bug in the UI?

Anyone else experience this same issue?

Thoughts and ideas very welcome :)

""Cheers
Gerardo

 

[velocity08]

Hi All

i believe ive found a solution and my above statement may be a UI bug.

if manually setting the properties via the shell everything works as expected.

from another post here on the forum.

Zvol Based LUN
Before growing a zvol based LUN, make sure that all initiators are disconnected. Stop the iSCSI service in Control Services.
Open Shell and identify the zvol to be grown:
zfs list -t volumeNAME USED AVAIL REFER MOUNTPOINTtank/iscsi_zvol 4G 17.5G 33.9M -
Then, grow the zvol. This example grows tank/iscsi_zvol from 4G to 6G:
zfs set volsize=6G tank/iscsi_zvolzfs set refreservation=6G tank/iscsi_zvol
Verify that the changes have taken effect:
zfs list -t volumeNAME USED AVAIL REFER MOUNTPOINTtank/iscsi_zvol 6G 17.5G 33.9M -
You can now start the iSCSI service and allow initiators to connect.

the extent is now expanded to 12 T and working as expected.

hope this helps somone else and that this behavour is picked up as a bug in the UI.

""Cheers
G

 

[JaimieV]

Hi Gerardo, well found! Glad you solved the issue even if it had to be the hard way...

If you have the energy left, you can log a bug about this at https://jira.ixsystems.com to help make sure it gets fixed. Devs do sometimes read here but that's the reliable way.

 

[velocity08]

Hi Gerardo, well found! Glad you solved the issue even if it had to be the hard way...

If you have the energy left, you can log a bug about this at https://jira.ixsystems.com to help make sure it gets fixed. Devs do sometimes read here but that's the reliable way.

Hi @JaimieV

yep i can do this a little later today.

The strange thing is that it allowed the 1st extension of the ZVOL from 6 > 9 TiB, my only thoughts are that it may be a regex issue in the GIU not allowing for double or more figures in the text field.

also the execution in terminal needed to be broken into 2 commands for what ever reason it didn't allow me to execute a single command.

Code:

zfs set volsize=6G tank/iscsi_zvolzfs set refreservation=6G tank/iscsi_zvol

needed to be:

Code:

# zfs set volsize=6G tank/iscsi_zvolzfs
# zfs set refreservation=6G tank/iscsi_zvol

for it to work.

""Cheers
G

 

[JaimieV]

Could certainly be that the GUI code also does one constructed combined 'zfs set' and failed, then misinterpreted the resultcode. You can maybe check using 'zpool history', see if it shows up there?

 

[velocity08]

interestingly enough it only has the 1 commend to extend from inital creation.

View attachment 36318

basically the UI restricted me from being able to extend past the 9 TiB previously mentioned.

So unless i'm mistaken it looks specifically like a UI issue, happy to be corrected.

Appreciate the added information and respectfully it was a very good suggestion could have gone either way :)

""Cheers
G