Several Nodes Setup
TeamCity allows configuring and starting another server instance in addition to the main one. Both servers will share the TeamCity data directory and the database. Using several node setup, you can:
improve the general TeamCity performance: configure a Running Builds Node, which handles all of the data produced by running builds (build logs, artifacts, statistic values) while the main server will handle all other tasks
set up a High-Availability TeamCity installation that will have zero read downtime: configure a Secondary Node allowing users read operations during the downtime of the main server, e.g. during the upgrade.