486 Implementing the IBM Storwize V5000 Gen2 with IBM Spectrum Virtualize V8.1
10.1 IBM FlashCopy
By using the IBM FlashCopy function of the IBM Spectrum Virtualize, you can perform a
point-in-time copy of one or more volumes. This section describes the inner workings of
FlashCopy and provides details about its configuration and use.
You can use FlashCopy to help you solve critical and challenging business needs that require
duplication of data of your source volume. Volumes can remain online and active while you
create consistent copies of the data sets. Because the copy is performed at the block level, it
operates below the host operating system and its cache. Therefore, the copy is not apparent
to the host.
While the FlashCopy operation is performed, the source volume is briefly halted to initialize
the FlashCopy bitmap, and then input/output (I/O) can resume. Although several FlashCopy
options require the data to be copied from the source to the target in the background, which
can take time to complete, the resulting data on the target volume is presented so that the
copy appears to complete immediately.
This process is performed by using a bitmap (or bit array), which tracks changes to the data
after the FlashCopy is started, and an indirection layer, which enables data to be read from
the source volume transparently.
10.1.1 Business requirements for FlashCopy
When you are deciding whether FlashCopy addresses your needs, you must adopt a
combined business and technical view of the problems that you want to solve. First,
determine the needs from a business perspective. Then, determine whether FlashCopy can
address the technical needs of those business requirements.
The business applications for FlashCopy are wide-ranging. Common use cases for
FlashCopy include, but are not limited to, the following examples:
Rapidly creating consistent backups of dynamically changing data
Rapidly creating consistent copies of production data to facilitate data movement or
migration between hosts
Rapidly creating copies of production data sets for application development and testing
Rapidly creating copies of production data sets for auditing purposes and data mining
Rapidly creating copies of production data sets for quality assurance
Regardless of your business needs, FlashCopy within the IBM Spectrum Virtualize is flexible
and offers a broad feature set, which makes it applicable to many scenarios.
10.1.2 Backup improvements with FlashCopy
FlashCopy does not reduce the time that it takes to perform a backup to traditional backup
infrastructure. However, it can be used to minimize and, under certain conditions, eliminate
application downtime that is associated with performing backups. FlashCopy can also transfer
the resource usage of performing intensive backups from production systems.
Important: Because FlashCopy operates at the block level below the host operating
system and cache, those levels do need to be flushed for consistent FlashCopies.
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