Administrator Guide

Data migration
This chapter describes data migrations and rebuild.
Topics:
• About data migrations
• Migrating thin-capable storage
• About rebuilds
• One-time data migrations
• Batch migrations
About data migrations
There are two types of data migrations:
● One time migrations - Begin a device migration immediately when the dm migration start command is used.
● Batch migrations - Are run as batch jobs using re-usable migration plan files. You can execute multiple device or extent
migrations using a single command.
One time migrations
One time migrations includes:
● Device migrations-Devices are 1:1 mapped, or RAID 1 devices built on extents or on other devices.
Device migrations move data between devices on the same cluster or between devices on different clusters. Use device
migrations to:
○ Migrate data between dissimilar arrays.
○ Relocate a hot volume to a faster array.
○ Relocate devices to new arrays in a different cluster.
Limitations
● Device migrations between distributed devices are not supported.
● Devices must be removed from consistency groups before they can be migrated between clusters.
Batch migrations
Batch migrations migrate multiple devices. Create batch migrations to automate routine tasks:
● Use batched device migrations to migrate to dissimilar arrays (you must configure the destination’s capacities to match the
capacity and tier of the source array), and to migrate devices between clusters in a metro node Metro.
Up to 25 local and 25 distributed migrations can be in progress at the same time. Any migrations beyond those limits are queued
until an existing migration completes.
NOTE: Devices must be removed from consistency groups before they can be migrated between clusters.
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