Google Search Appliance Upgrade and Migration Handbook - Manual (Page 9)

Upgrading multiple environments
This section applies to deployment architectures involving multiple environments with various purposes, such
as development, testing, and production.
Once a version upgrade or patch release is applied to the GSA, it cannot be reverted to a previous version.
Additionally, changes/additions to GSA functionality might occasionally impact the existing functionality of a
search solution, for example one where the GSA has been tightly integrated within other applications. For
these reasons, version upgrades should be applied through development and testing environments, and first
be tested rigorously before updating a production search appliance.
In a deployment where a production environment contains one or more backup search appliances for
disaster recovery or failover, the following steps are recommended:
1. Switch serving to a backup search appliance
2. Update the production search appliance first, before upgrading a backup search appliance
This process allows users to continue using search on the existing, familiar version of the search appliance
while verification and cutover of the new version in production is taking place. If mirroring is in use, refer to
Upgrading an inter­connected GSA network .
Upgrading an interconnected GSA network
Special considerations must be observed when upgrading deployment architectures involving two or more
GSAs connected to each other by the use of Mirroring, Distributed Crawling and Serving, or Unification.
In general, the primary GSA(s) in an interconnected GSA network should be upgraded before
secondary/backup GSAs are upgraded.
However, each new release has Update Instructions that provide detailed steps for upgrading interconnected
GSAs. It is important that these steps are closely followed, as performing an upgrade incorrectly may result
in the integrity of the GSA network and search index being compromised, potentially requiring a complete
re­indexing of content. If in doubt, contact Google Enterprise Support or a GSA Qualified Deployment
Specialist for clarification.
Upgrading with connectors or feeds
This section applies to deployment architectures involving the use of GSA connectors or feeds.
If your environment uses GSA connectors or feeds, the downtime associated with upgrading a search
appliance must be taken into account and planned for. There are two considerations for downtime when
using connectors or feeds:
● Indexing of content
● Serving of content, where connectors are used for authentication and authorization
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