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: 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. 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. 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 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 .  Size:  An image mode volume must be at least 512 bytes (the capacity cannot be 0) and  always occupies at least one extent. 292  Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1 -grainsize This parameter sets the grain size in kilobytes (KB) for a  thin-provisioned volume (optional). -autoexpand This parameter specifies that thin-provisioned volume copies  automatically expand their real capacities by allocating new extents  from their storage pool (optional). -rsize This parameter makes the volume a thin-provisioned volume. If this  parameter is missing, the volume is created as fully allocated.