Memory failures cause significant issues in current data centers, including valuable data loss and application outages. A rack of memory supporting 8TB of DRAM and would include over 64,000 DRAM devices. Even with a DRAM device MTBF of 1000 years, there would be multiple failures each year.

Violin Switched Memory (VXM) dramatically reduces these device failure issues through the use of RAID technology specifically designed for memory. Data is automatically striped across DRAM or Flash modules in a way where any module can fail and be replaced without loss of data or a service outage. Specific advantages of VXM RAID are:

• Data protection: Data is protected by RAID algorithms
• Outage Prevention: Modules (VIMMS) can be replaced without impacting the servers or applications.

The VXM topology is unique and based on 3 port switches in each of the Violin Intelligent Memory Modules (VIMMs). Each VIMM has a Violin Buffer (VB) device which both implements the 3 port switch and also provides local memory controller functions. The central memory controller provides higher level functions such as the mapping of logical address space to the specific physical VIMMs and memory devices.

The topology shown below allows any two modules within a large network (84 modules) to fail without loss of connectivity to any of the other modules. This allows the RAID algorithms to operate over a group of 5 of modules.

Violin Switched Memory (Patent Pending)

In the event of a module failure, the RAID group is rebuilt within a few minutes — much faster than hard disk storage—into any of the global spare modules within the system. The faulty modules can then be removed while the system is in service and a new module is inserted.