Google Search Appliance Upgrade and Migration Handbook - Manual (Page 8)

Analyze impact and changes required for the upgrade
Once the scope of the upgrade has been defined, an impact analysis should be performed to determine the
changes that will be needed to be made to the GSA environment to accommodate for the upgrade.
Common considerations when performing a GSA upgrade include:
Re­indexing content
● A complete re­index may be a requirement of upgrading to the new GSA software version. The GSA
software update instructions typically provide detail on this requirement.
● Some new features require the re­indexing of content. For example, enabling Entity Recognition and
Document Previews in v7.0 require re­indexing content since these features involve index­time
processing.
Front­end modification
● Enabling new user interface features will always involve changes to existing GSA front­ends
● For custom user interfaces (custom XSLT or custom application layers) the complexity of these
changes may be anything from trivial to highly complex, depending on the feature.
● For implementations involving custom XSLT modifications, it is recommended that the new version’s
default XSLT stylesheet be used as a starting point, and customizations be re­integrated into it.
This is typically a simpler approach than determining the changes required to implement the new
feature into an existing XSLT stylesheet.
Feed changes
● When new features to the GSA feeds protocol are introduced, custom feeds should be analyzed to
determine whether they may benefit from the new changes. For example, in v7.0, new ACL features
such as DENY ACLs and ACL inheritance were introduced and offer significantly increased
flexibility for designing feeds for secure content.
● Whilst updates to the GSA feed protocol are generally backward compatible, changes that are
introduced to the protocol should be analyzed to ensure that existing GSA feeds are not impacted.
Connector upgrades
● New GSA upgrades will typically support any existing versions of Google connectors. However, it is
recommended that version compatibility of connectors be confirmed prior to upgrading to a new
GSA version.
Define an upgrade strategy
The goal of defining an upgrade strategy is to determine the best process to upgrade the appliances in a
GSA environment whilst having minimal impact to search users and dependent systems.
It is important to understand the potential impacts of the upgrade process to the GSA deployment
environment. This section discusses a number of scenarios, where special considerations should be made
when upgrading a search appliance.
● Upgrading multiple environments
● Upgrading an inter­connected GSA network
● Upgrading with connectors or feeds
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