McData switch simplifies SAN expansion

As SANs expand, it's not uncommon for a significant portion of switch ports to be consumed by connections to other switches. This is due not only to the relatively low port counts of typical FC (Fibre Channel) switches, but also because of the need for higher speed interconnects, which are often achieved by bonding multiple ports together.

There is a new option to eliminate switch-port congestion and SAN fumbling, however. McData's just-released Intrepid i10K Director, an enterprise-class FC switch, has the capacity to consolidate multiple SANs. It also includes features taken for granted in the Ethernet switch world, such as creation of the equivalent of VLANs by partitioning the SAN fabric into multiple fabrics, and features for remote sites that make data distribution and replication easier, faster, and more secure. 

The i10K's uniqueness, though, lies in enabling gradual moves from SAN islands to a centralized SAN architecture. For instance, you could start with one connected SAN, create a second partition, add a second SAN, and then eventually merge the two partitions, without ever disrupting access to data.

The steep price is sure to give pause, but if you do the math, it works out to about the same per-port cost as an eight-port FC switch -- but you also get the i10K's enterprise features and expandability. Based on the scalability and solid performance I saw during testing, the i10K is worth it.

Expanding on the Basics

The i10K is a 14U monster with all the features you'd expect in an enterprise-class network switch: redundant power supplies, fans, control and switching modules, hot-swap capability. It delivers as many as 256 nonblocking ports of 1/2/4Gbps FC -- more than double the next best switch's total of 112 nonblocking 1/2Gbps ports -- or as much as 32 ports of 10Gbps FC, and supports FICON (Fiber Connectivity) and iSCSI (Internet SCSI). Upgrades to code on the switch take place without interrupting data flow and include backups of the old versions with easy revision if necessary.

There are two control processors on the front and eight slots for blades (Line Modules), plus four slots on the back for switching modules -- the switching fabric can be expanded along with the number of ports. Each line module supports eight paddles, which can be eight-port 1/2Gbps paddles, eight-port 1/2/4Gbps paddles (scheduled for release in Q1), or two-port 10Gbps paddles.

The 1/2/4Gbps and 10Gbps paddles can coexist on the same line card, so the switch expands in relatively small increments (eight ports at a time), all the way to 256 ports.

The i10K also supports a very large number of BB (buffer-to-buffer) credits, which are buffers that determine the maximum run length of connections. With 1,373 credits per processor (two to a blade), each blade can support two 190km connections at 10Gbps, or two 1,100km connections at 2Gbps, or two 2,200km connections at 1Gbps, over a dark fiber connection.

This will be a big benefit for users who need to set up replication over long distances for disaster recovery or Sarbanes-Oxley compliance. In terms of long-distance connections, the i10K is better than most other switches by one or two orders of magnitude.

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