Architecture
Nextra is built as a grid-based storage system of independent modules.
The modules are implemented using off-the-shelf, Intel-based servers within a customized, Linux-based architecture, and are interconnected over redundant Gigabit Ethernet switches. The modules act jointly as a large data grid devoid of a common backplane. The grid is managed by sophisticated distributed algorithms and delivers enterprise-class performance,
reliability, and functionality.
A Nextra system can be built modularly from the following components:
- Data modules. The data modules are Intel-based servers with a large number of disks. They are responsible for storing the data and performing all advanced storage functionality, such as redundancy, snapshots, caching, etc.
- Interface modules. The interface modules are also implemented as Intel-based servers, responsible for accepting host I/O commands (via FC or iSCSI) and forwarding them to the appropriate data module. Interface modules do not handle any storage functionality; they act as unintelligent routers.
- Gigabit Ethernet switches. The switches are the interconnect between all the data and interface modules.
- UPS units. The UPS units ensure that the system has enough time to de-stage all cached data upon a power outage.
Nextra provides a management function that handles all system-wide management functions: allocating new volumes, etc. In keeping with Nextra's streamlined, standardized approach to architecture, the function does not have its own dedicated hardware. Instead, it runs on one of the standard modules and, in the event of failure of that module, automatically restarts on another module.
