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CensorNet becomes fault tolerant

Published in CensorNet Professional on August 20, 2009 by Administrator

Our Development Team have been looking into making the CensorNet fault tolerant. This means that the failure of a device does not need to lead to the complete loss of the service. The system works by having two servers, one is deemed to be a master, with the other a slave. Each server has its own IP address and there is an additional IP address for the cluster as a whole. Users point their browsers at the cluster’s IP address. In that way, if the system switches to the backup node, there is no loss of service and it is all transparent to the users. During normal operation, the CensorNet writes lots of transactions to its database. It also writes configuration changes to this same database. In the event of a fail-over you would want this data to be up to date. We achieve this by using some readily available third party software which effectively turns the secondary node into a mirror of the first. As a result, if the node currently acting as the master suddenly fails, the secondary node takes over exactly where the primary left off with no loss of data. Now you can repair the old primary in your time and bring it back into the cluster when ready. When bought back in, it will be quietly bought up to date before the system switches back again. Obviously, there is some cost involved in having this fault tolerant service. Interested users should speak to our Sales Team for further details.