Announcement press release was February 5, 2015. First ship was sometime in March. This is the next generation follow-on to the VDX 6740. A snippet from the datasheet shows the info on packet buffers:

    Optimized Packet Buffer and Latency for Better Application Performance

    Brocade VDX 6940 Switches offer a unique balance between two conflicting attributes—-buffer and latency. Niche products with very high buffer often suffer from high latency, and products with ultra-low latency are not a good fit for data centers with bursty traffic. Brocade VDX 6940 Switches, with a purpose-built data center chip, excel in optimizing buffer and latency to deliver better application performance. These switches deliver 700 ns any-port-to-any-port latency. In addition, they offer an industry-leading 24 MB deep buffer. This provides the buffering capacity to handle increases in traffic, especially during peak times when ports are congested, allowing traffic to be distributed across the ports. Brocade VDX 6940 Switches also feature a single ASIC design, instead of multiple ASIC designs commonly found in other switches. This improves performance since all ports communicate via the one ASIC.

A cautionary note about vendor claims in general and this switch in particular appears in Ivan Pepelnjak's blog. The claim that big buffers cause high latency is [cough] bullshit. A comparison of the 6940 with switches pegged as the competition was offered by Brocade. A nit-pick note: system buffer is a poorly chosen name. System buffer is memory used by the switch CPU for control plane functions. This is packet buffer data plane memory.

The Command Reference Manual page for one of the buffer control commands shows the per port limit.