292 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
7.8.3  Creating a thin-provisioned volume
Example 7-4 shows an example of creating a thin-provisioned volume. This requires the 
following parameters to be specified:
-rsize This parameter makes the volume a thin-provisioned volume. If this 
parameter is missing, the volume is created as fully allocated.
-autoexpand This parameter specifies that thin-provisioned volume copies 
automatically expand their real capacities by allocating new extents 
from their storage pool (optional).
-grainsize This parameter sets the grain size in kilobytes (KB) for a 
thin-provisioned volume (optional).
Example 7-4   Using the command mkvdisk
IBM_Storwize:ITSO:superuser>mkvdisk -mdiskgrp Pool0 -iogrp 0 -vtype striped -size 10 -unit 
gb -rsize 50% -autoexpand -grainsize 256
Virtual Disk, id [9], successfully created
This command creates a thin-provisioned volume with 10 GB of virtual capacity. The volume 
belongs to the storage pool that is named Site1_Pool and is owned by input/output (I/O) 
Group io_grp0. The real capacity automatically expands until the real volume size of 10 GB is 
reached. The grain size is set to 256 KB, which is the default.
7.8.4  Creating a volume in image mode
Use image mode volume to bring a non-virtualized disk (for example, from a pre-virtualization 
environment) under the control of the IBM Spectrum Virtualize system. After it is managed by 
the system, you can migrate the volume to the standard managed disk. 
When an image mode volume is created, it directly maps to the thus far unmanaged MDisk 
from which it is created. Therefore, except for a thin-provisioned image mode volume, the 
volume’s LBA x equals MDisk LBA x. 
Disk size: When the -rsize parameter is used to specify the real physical capacity of 
a thin-provisioned volume, the following options are available to specify the physical 
capacity: disk_size, disk_size_percentage, and auto.
Use the disk_size_percentage option to define initial real capacity by using a percentage 
of the disk’s virtual capacity that is defined by the -size parameter. This option takes as 
a parameter an integer, or an integer that is immediately followed by the percent (%) 
symbol.
Use disk_size option to directly specify the real physical capacity specifying its size in the 
units defined by using the -unit parameter (the default unit is MB). The -rsize value can 
be greater than, equal to, or less than the size of the volume.
The auto option creates a volume copy that uses the entire size of the MDisk. If you specify 
the -rsize auto option, you must also specify the -vtype image option.
An entry of 1 GB uses 1,024 MB.
Size: An image mode volume must be at least 512 bytes (the capacity cannot be 0) and 
always occupies at least one extent.