Google Search Appliance Configuring GSA Mirroring version 7.2 - Manual (Page 5)

Google Search Appliance: Configuring GSA Mirroring 5
Requirements for GSA Mirroring
GSA mirroring requires a sustainable 1 MB per second file transfer rate between the master Google
Search Appliance and each replica search appliance. To determine whether a network can provide the
required file transfer rate, we recommend that you measure the rate by transferring files on your
network between the subnets where the search appliances are located. If the file transfer requirement
is not met by the network, the mirroring feature might not work as expected.
Your installation must meet the following requirements to participate in a GSA mirroring configuration:
• All search appliances must be on the same software version. For example, you cannot have one
search appliance in the configuration on version 6.4 and another on version 6.8, or one search
appliance on 6.2.0.G14 and another on 6.2.0.G36. When you update from one software version to
the next, ensure that you update all search appliances in the configuration.
• All search appliances in the configuration must be licensed for the same document count.
• The search appliances must be able to contact each other on TCP ports 8000 and 8443 while
mirroring is being set up, and any time a change to the mirroring configuration is made.
The search appliance models you have determine which machine is the master and which can be
replicas. The primary consideration for choosing the master is that its license count cannot exceed the
maximum license limit of the replica search appliance.
About GSA Mirroring
When GSA mirroring is enabled, the search index and configuration information are mirrored from the
master search appliance to the replica nodes. The search appliances are synchronized on a regular
basis, with some delay, using checkpoint files that are produced on the master node. The amount of
data synchronized among the search appliances depends on the delta between the index on the master
search appliance and the indexes on the replica nodes. When the delta is larger, more data is
synchronized. Consider the following three scenarios.
In scenario one, two search appliances have been in a mirroring configuration for some time and their
indexes are similar and in a comparatively steady state. The indexed content does not change radically.
In this situation, the delta between the two search appliances is small. When the two search appliances
are synchronized, the checkpoint files are small and the synchronization process takes place quickly.
Master Search Appliance Replica Search Appliances
GB-7007 GB-7007
GB-9009
G100
G500
GB-9009 GB-9009
G500
G100 G100
G500
GB-7007 (supported only if license count on the master is less
than 10 million)
GB-9009
G500 G500