Google Search Appliance Upgrade and Migration Handbook - Manual (Page 14)

Chapter 4 ­ Migration Planning
Overview
The following sections provide guidance in migrating Google Search Appliances in various deployment
scenarios.
Migration methods
There are two methods of migrating a single search appliance to another:
● Migrating search index and configurations
● Migrating configurations only
Migrating search index and configurations
GSA Mirroring is a feature primarily used to provide high availability and high capacity serving, but it can
also be used for migrating configurations and search indexes between appliances. In fact, mirroring is the
only means to completely migrate an index from one Google Search Appliance to another, and should be
used for GSA migration whenever possible.
This migration method is most appropriate when:
● Re­indexing of all content takes significant time, due to large index size or slow crawl rates
● No changes are planned to deployment architecture and content source integration
● Features in the new software release on the new appliance(s) do not require re­indexing of content
(refer to version release notes for guidance)
Advantages of this migration method:
● Saves time in content indexing (mirroring is much faster than re­indexing of content)
● Minimal user impact on existing production search experience, as the new appliance’s search index
will be an exact “replica” of the existing appliance
Disadvantages of this migration method:
● Procedure is more complicated than migrating configuration only
● The crawl cycle on the production system will be temporarily paused and new content will not be
acquired during the migration process
Requirements
For mirroring to be configured, both search appliances must meet the following requirements:
● They must be on the same GSA version, and be of v6.8 or higher
● They must be of compatible search appliance models
● The master GSA must be licensed for equal or lower document count than the replica GSA
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