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Why HP Lefthand Networks

For many years we had watched the SAN market place with some degree of envy. While it was clearly a technology we wanted to be able to offer to our clients, the high cost and complexity of the solutions made that impossible. However, like all IT technologies, it was merely a case of waiting for the cost and complexity to reduce to a point where the ability to purchase became feasible. At the same time, the capabilities and management features continued to improve.


The original SAN technology was based on Fibre Channel (FC) - a costly and complex technology. iSCSI arrived on the scene a number of years ago and while much easier to manage, it did not have the raw performance that FC gave to the SAN. With Gigabit networking now commonplace and iSCSI having matured, the performance it offers is now more than capable of running the type of SAN that we required.

Lefthand Networks were the first SAN company to develop an iSCSI solution (SAN/IQ) from the ground up. Many other vendors have had to offer this as a bolt-on and as such, the implementation is nowhere near as integrated as the Lefthand offering.

Lefthand offer a range of appliances that will easily cater for our customer requirements.

Network RAID

One of the key features of their solution is their Network RAID functionality. Most people are familiar with RAID in terms of hard drives in a server, where the data is striped across a number of hard drives. In the event of a hard drive failing, the server continues to run. With hot-swap drives, the faulty drive can be replaced and the data is re-striped while the server continues to run.

Lefthand have taken this concept and applied it to their SAN appliances. With two appliances, data can be mirrored in real time across both. With three or more appliances, data can be striped. With a multitude of RAID options, individual storage pools can be mirrored or striped across multiple devices as the criticality of the data on them dictates. This can all be reconfigured on the fly with no downtime on the SAN.

Virtual SAN

In addition to the traditional SAN server appliances, Lefthand also make their SAN applications available as virtual machines. This allows a VMware ESX with VMotion capabilities to be constructed using just two servers (where it would typically take four). Many organisations would benefit from being able to virtualise their servers and have either VMotion capabilities, or just the ability to manually move machines in the event of an equipment loss. Being able to do this for a small network in as few as two servers opens up a multitude of possibilities while not breaking the bank.

Exmos has a two node SAN/VM network with both Virtual and Physical servers to demonstrate this technology. We use this as our main production network, so prospective customers can not only see this technology in action, but see it running a business critical network in a real-life scenario.