3PAR InForm® OS 2.3.1 Concepts Guide (320-200112 Rev B, February 2010)

12.6
Thin Conversion
3PAR InForm OS Concepts Guide InForm OS Version 2.3.1
12.5.1 Assessment
Before converting your volumes you must determine the benefits of the conversion process.
The potential benefits of zeroing free space prior to copying or migrating the data to a TPVV
depends on the amount of allocated but unused space. If there is relatively little unused space
in the allocated physical space then there is little benefit to zeroing the free space to recapture
this relatively small amount of space. Many volumes that have been in use for a long time have
significant amounts of allocated but unused space. If there is a large amount of unused space
in the allocated physical space then zeroing the data prior to copying the data results in a
substantial reduction in the amount of used space.
12.5.2 Data Preparation
Prepare your data for copying by removing unnecessary data. Perform clean-up tasks on the
source volume by:
■ Emptying trash cans or permanently deleting files.
■ Archiving unused files.
■ Shrinking databases.
■ Deleting temporary files.
12.5.3 Zeroing Unused Space
Use a host application to write zeros to the allocated but unused volume space. InServ F-Class
and T-Class Storage Servers detect and discard the zeros during the volume copy operation.
12.5.4 Creating a Physical Copy
After writing zeros to the allocated but unused space, the source volume is ready for the final
phase of conversion. You create a TPVV physical copy of the source volume to convert the
source volume to a TPVV. When you create a physical copy, InServ F-Class and T-Class Storage
Servers automatically detect the zeros and do not allocate space for them in the physical copy.
The result is a TPVV that is much smaller than the original volume.
Thin Conversion tasks can be performed with both the 3PAR InForm Command Line Interface
(CLI) and the 3PAR InForm Management Console. Refer to the 3PAR InForm OS CLI
Administrator’s Manual and the 3PAR InForm Management Console Online Help for
instructions on how to perform these tasks.