Simultaneous Processing Of Multiple Thin Image Pair Tasks; Pair Operations When Pairs Are Cascaded - Hitachi VSP G1000 User Manual

Note: Using external volumes increases the likelihood of a failure, and
disaster recovery is more complex and challenging. Using multiple external
volumes as pool-VOLs in a pool increases the likelihood of the pool being
blocked.
To minimize the adverse effects of failure, use only one pool per external
storage system. An external pool-VOL that is blocked due to a failure blocks
the pool. You must restore blocked pools.
For more information about external storage systems and disaster recovery
methods for external volumes, see the Hitachi Universal Volume Manager
User Guide.

Simultaneous processing of multiple Thin Image pair tasks

Some Thin Image pair task operations are processed in the background after
the requested task is accepted. The total number of instances of each pair
task that can be simultaneously processed in a storage system is limited by
the number of MP blades (or units) in the storage system.
Note: The terms "blade" and "unit" refer to the same hardware on different
VSP storage systems. The term "blade" is used for VSP G1000, G1500, and
VSP F1500, and the term "unit" is used for VSP G200, G400, G600, G800.
For each of the following pair tasks, the number of simultaneous instances
processed in the background is equal to the total number of MP blades (or
units) in the storage system:
• Creating pairs.
• Restoring pairs.
• Deleting snapshot data and deleting pairs.
When you execute additional pair task operations above these limits, the
tasks are processed in the order requested.
Related tasks
• Creating Thin Image pairs using Device Manager - Storage Navigator
page 130
• Restoring Thin Image pairs
• Resynchronizing Thin Image pairs
• Deleting Thin Image pairs

Pair operations when pairs are cascaded

The following table explains pair operations according to the pair status. The
status of pair B is SMPL.
Hitachi Thin Image User Guide for Hitachi Virtual Storage Platform G Series and F Series
on page 141
on page 146
Thin Image system and planning requirements
on page 144
on
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