The first part of this blog post explained the common design approaches used for a non-disruptive upgrade in enterprise storage. Further to the discussion, there are some unique approaches for a risk-free enterprise storage upgrade, which we will detail in this blog post.
Innovative Hardware Redundancy
Most enterprise array architectures are built around a controller-pair oriented hardware design. Whether these are active/active or active/passive, software upgrades in traditional systems occur in a rolling manner. This means the end-user first upgrades one controller followed by the other upon completion.
During the first controller’s upgrade, the system goes to ‘panic mode’ – an event that would take place during controller failure. Commonly, this means that the system turns from the high performance ‘write back’ cache mode to the low performance ‘write-through’ cache mode. This secures data integrity impacting application performance in traditional dual-controller architecture upgrade scenarios. This also means systems need to undergo regression testing to operate smoothly in two different configurations – one with the same firmware in all controllers and one with two different versions running simultaneously on the controllers.
Infinidat’s InfiniBox uses an architecture with three controllers, all of which operate on active/active/active mode during an operation. All the controller related upgrades take place together without disrupting the application services.
Upgrading controller firmware is a milliseconds’ process. Simultaneously, all the controllers are upgraded before any application expires and ensures that application services run without disruption. This approach does not require inter-generational regression testing since customers will never be running different releases on different controllers simultaneously. This way, the system never goes into the low performance ‘write-through’ cache mode.
Most of the systems Infinidat sells consolidate multiple workloads. Due to this, the average storage capacity among their customers is naturally higher than that of the other enterprise storage vendors. Infinidat ships all systems with the fully configured system back end to better address their customers’ growing storage capacity needs. When customers require more capacity, they procure the storage and pay for it. It means that capacity expansion is a simple change in the software, and no field engineering activities are connected to it. This also mitigates the risks associated with manual upgrades.
Among the storage vendors who have arisen in the last decade, only a few match the development track record and expertise of Infinidat in enterprise storage solutions. Many other system features support its 100% data availability guarantee, and a non-disruptive upgrade is just one of those.