Administrator Guide

Table Of Contents
Consistency Groups
This chapter describes how to manage and operate metro node consistency groups.
Topics:
About metro node consistency groups
Properties of consistency groups
Manage consistency groups
Operating a consistency group
About metro node consistency groups
Metro node consistency groups aggregate volumes to enable the application of a common set of properties to the entire group.
Figure 5. Metro node Consistency group
Synchronous consistency groups
Synchronous consistency groups provide a convenient way to apply rule sets and other properties to a group of volumes in a
metro node Local or metro node Metro.
Metro node supports up to 1024 synchronous consistency groups.
A synchronous consistency group:
Contains up to 1000 virtual volumes.
Contains either local or distributed volumes, (but not a mixture of both).
Contains volumes with either global or local visibility.
Uses write-through caching (known as synchronous cache mode in the metro node user interface).
Write order fidelity is maintained by completing all writes to disk before acknowledging the write to the host.
The following figure shows a synchronous consistency group that spans two clusters in a metro node Metro configuration.
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64 Consistency Groups