100G zvol takes up 202G of space

[SFAJeff]

Not sure what is going on but I created a 100G zvol on a 240G SSD. After creation I installed Windows Server 2008 r2 in a VM using the zvol as a disk. After installation the GUI showed a warning that the SSD was at 94% of capacity. I am running FreeNAS 11.1-U1

Anyone have any idea what is going on?

The output of zfs get all is below:

Code:

NAME			 PROPERTY				 VALUE					SOURCE

vms/windows2008  type					 volume				   -

vms/windows2008  creation				 Mon Feb  5  0:02 2018	-

vms/windows2008  used					 202G					 -

vms/windows2008  available				10.7G					-

vms/windows2008  referenced			   202G					 -

vms/windows2008  compressratio			1.02x					-

vms/windows2008  reservation			  none					 default

vms/windows2008  volsize				  100G					 local

vms/windows2008  volblocksize			 512					  -

vms/windows2008  checksum				 on					   default

vms/windows2008  compression			  lz4					  inherited from vms

vms/windows2008  readonly				 off					  default

vms/windows2008  copies				   1						default

vms/windows2008  refreservation		   150G					 local

vms/windows2008  primarycache			 all					  default

vms/windows2008  secondarycache		   all					  default

vms/windows2008  usedbysnapshots		  0						-

vms/windows2008  usedbydataset			202G					 -

vms/windows2008  usedbychildren		   0						-

vms/windows2008  usedbyrefreservation	 0						-

vms/windows2008  logbias				  latency				  default

vms/windows2008  dedup					off					  inherited from vms

vms/windows2008  mlslabel										  -

vms/windows2008  sync					 standard				 default

vms/windows2008  refcompressratio		 1.02x					-

vms/windows2008  written				  202G					 -

vms/windows2008  logicalused			  27.5G					-

vms/windows2008  logicalreferenced		27.5G					-

vms/windows2008  volmode				  default				  default

vms/windows2008  snapshot_limit		   none					 default

vms/windows2008  snapshot_count		   none					 default

vms/windows2008  redundant_metadata	   all					  default

vms/windows2008  org.freenas:description						   local

 

[m0nkey_]

Snapshots? zfs list -t snapshot

 

[rs225]

volblocksize = 512

The default is 8K, and that should be considered the minimum.

 

[SFAJeff]

No snapshots. The blocksize needs to be 512 or Windows 7 / 2008 will not install.

 

[SFAJeff]

I was able to reproduce by creating another 100G zvol in my main pool. After installing Windows Server 2008 r2 the zvol took up 150G. After installing the first round of windows updates the zvol was taking up 272G and after the second round of updates it is now taking up 284G.

Steps to reproduce:

Create a 100G zvol and set sector size to 512b.
Install Windows Server 2008 r2 Full Install
Install Windows Updates

Is this a bug or am I missing something?

 

[Patrick M. Hausen]

You don't need to set the volblocksize to 512 to install Windows. Rather edit the device in the VM device settings and set the disk sectorsize to 512 there.

Patrick