Keeps Backup Windows from Expanding as Data Grows
ExaGrid is the only solution that uses an architecture which prevents your backup windows from exploding as data grows by adding full appliances to maintain consistently fast backup performance.
With ExaGrid's grid-based architecture, each appliance contains processing power, memory, bandwidth, and disk. When the system needs to expand, additional appliance nodes are attached to the grid, bringing with them additional processing power, memory, and bandwidth, as well as disk. As depicted in the diagram to the right, this type of configuration allows the system to maintain all the aspects of performance as the amount of data grows.
ExaGrid's grid-based configuration stands in contrast to the controller / disk shelf model, which is the other architectural alternative available with disk-based backup appliances. With the controller-shelf model, all of the processing power, memory, and bandwidth are contained in the controller. When data grows such that you need to expand the system, additional disk shelves are added to the controller (see Legacy Architecture - Single Controller diagram).
Because you have a static amount of processing power, memory, and bandwidth for a given system even as the amount of data is growing, this results in one or both of the following negative effects: (i) as the amount of backup data grows with a constant level of processing power, memory, and bandwidth, the backup starts to take longer and longer; (ii) the amount of processing power, memory, and bandwidth must be over-provisioned when the system is first acquired to allow for future data growth, but resulting in a more expensive system at the time of purchase. In addition, each controller can only handle a certain amount of disk, and when the customer's data increases beyond that level, the entire system must be swapped out for a new one in a costly "forklift" upgrade.
This cycle of "Grow / Break / Replace" is further depicted in the diagram below. Time (as data grows) is on the X-axis and backup performance is on the Y-axis. As shown on the left, with the single controller architecture, as data grows over time and you add only disk shelves, the backup performance steadily drops--to the point where backup "breaks" due to no longer meeting the backup window requirement. That requires replacement of the controller via costly forklift upgrade to the next larger controller--and then the Grow / Break / Replace cycle continues again. In contrast, with ExaGrid's GRID architecture, full appliances are added seamlessly and performance scales exponentially with no degradation in backup performance and no forklift upgrades.