## 7.9.17 Migrating a fully managed volume to an image-mode volume 

Migrating a fully managed volume to an image-mode volume enables the IBM Spectrum Virtualize system to be removed from the data path. This feature might be useful when you are using the IBM Spectrum Virtualize system as a data mover. 

To migrate a fully managed volume to an image-mode volume, the following rules apply: 

GLYPH<SM590000> Cloud snapshots must not be enabled on the source volume. 

GLYPH<SM590000> The destination MDisk must be greater than or equal to the size of the volume. 

GLYPH<SM590000> The MDisk that is specified as the target must be in an unmanaged state. 

GLYPH<SM590000> Regardless of the mode in which the volume starts, it is reported as a managed mode during the migration. 

GLYPH<SM590000> If the migration is interrupted by a system recovery or cache problem, the migration resumes after the recovery completes . 

Example 7-31 shows a migratetoimage  command that migrates the data from volume_A  onto mdisk10 , and puts the MDisk mdisk10  into the STGPool_IMAGE  storage pool. 

IBM_2145:ITSO_CLUSTER:superuser>migratetoimage -vdisk volume_A -mdisk mdisk10 -mdiskgrp STGPool_IMAGE 

## 7.9.18 Shrinking a volume 

Use the shrinkvdisksize  command to reduce the capacity that is allocated to the particular volume by the amount that you specify. You cannot shrink the real size  of a thin-provisioned volume to less than its used size . All capacities (including changes) must be in multiples of 512 bytes. An entire extent is reserved even if it is only partially used. The default capacity units are MBs. 

You can use this command to shrink the physical capacity of a volume or to reduce the virtual capacity of a thin-provisioned volume. These changes do not alter the physical capacity that is assigned to the volume. Use the following parameters to change volume size: 

GLYPH<SM590000> For a fully provisioned volume, use the -size  parameter. 

GLYPH<SM590000> For a thin-provisioned volume’s real capacity, use the -rsize  parameter. 

GLYPH<SM590000> For a thin-provisioned volume’s virtual capacity, use the -size  parameter. 

When the virtual capacity of a thin-provisioned volume is changed, the warning threshold is automatically scaled. 

If the volume contains data that is being used, do not shrink the volume without backing up the data first. The system reduces the capacity of the volume by removing extents as follows: 

GLYPH<SM590000> Arbitrarily chosen extents, or 

GLYPH<SM590000> Extents from those allocated to the volume. 

You cannot control which extents are removed. Therefore, you cannot assume that it is unused space that is removed. 

Image-mode volumes cannot be reduced in size. To reduce their size, you must first migrate them to fully-managed mode. 

