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In this article, we will discuss what IBM Flashcopy is, how it works and the practical use cases of IBM Flashcopy. IBM FlashCopy for IBM i is used to make a point in time copy of a source volume over the content of a target volume is lost. Although the copy operation takes time, the resulting data at the target appears as though the copy was made instantaneously.
So this allows an effective backup to disk which remains online until the next Flashcopy is taken. This ‘snapshot’ type technology is not new but has traditionally been difficult to introduce in an IBM i environment which has historically run on internal disk. With IBM POWER Servers being increasingly supported by IBMs Storwize product range (V7000, V5000 etc), Storwize’s Flashcopy capability can provide near real-time backups with little or no planned downtime. This Flashcopy capability is not limited to supporting IBMi environments, indeed it can support any type of Server environment. When an IBM i partition is copied using Flashcopy, the entire partition is copied: SLIC, OS, Licensed Programs, system and IP settings, user data, spool files, jobs on job queues.
The two main uses are:
When an IBM i partition is copied, it provides a backup to disk. If you want this written to tape, you need to boot this copy to a separate partition to then present a tape device to it.
This process can be automated and can also interact with BRMS to ensure the backup appears to have been run on your actual production partition.
To ensure data is being backed up in a consistent state, it’s highly recommended to quiesce the applications before performing the Flashcopy, just like a save-while-active checkpoint. The application only needs to be down for less than 60 seconds while the flashcopy is taken. So you can perform a genuine full system save with the smallest outage by using Flashcopy.
You can take a one-off Flashcopy to provide a copy of your production system. This can then be booted to a separate partition and given a different system name and IP address to create a test system. Use this to test IBM PTFs, OS upgrades, and other application changes. If you decide to re-run the Flashcopy it returns the data to a copy of production and you can test again.