University opts for Stormagic software iSCSI SAN

When direct-attached storage at the University of Liverpool started causing throughput issues, the university opted for an iSCSI SAN from StorMagic iSCSI.

The University of Liverpool's computer science department has implemented a StorMagic SM Series iSCSI software-based SAN to replace its existing direct-attached storage. The solution, which consists of software plus generic hardware, was chosen over storage products from incumbent server supplier Hewlett-Packard. The solution also allowed the department to save 50% on the cost of expanding its DAS provision.

The department has more than 500 undergraduate students, 44 permanent members of staff and 50 research assistants/PhD students and runs Window servers plus Linux Fedora Core 6 clusters. Its storage infrastructure consisted of two 14-disk Transtec RAID boxes, providing a total 4 TB directly attached to two servers.

We didn't go for the likes of HP, despite being a HP server shop, because it was an expensive solution that seemed like it would lock us in.
Kenneth Chan
principal experimental officerUniversity of Liverpool
The chief limitation for the department -- which generates vast amounts of data in compute-intensive operations running 24/7 -- was that to add capacity it needed to shut down, replace disks and start up again. Also, because storage was attached directly to servers, there were throughput issues, said, Kenneth Chan, principal experimental officer in the department.

Chan said, "The existing RAID systems were directly attached to the servers and as a result, they were becoming marginalised. We decided that networking our storage would be more effective."

White-box storage array
The department chose to replace its DAS storage with Stormagic's SM Series iSCSI SAN software. Stormagic products are available as software-only, but in this case, the vendor supplied the customer with a white-box storage array from Taiwanese hardware case maker Chenbro Micom, in a solution which is licensed for 3 TB of capacity. The Stormagic software is compatible with the department's Windows and Linux servers.

Today's iSCSI storage networks use existing Ethernet cabling and switches and offer a much cheaper alternative to Fibre Channel storage products. Software-based products are also far less expensive than buying dedicated hardware products from the major vendors. These reasons were the main ones the department chose the Stormagic product, said Chan.

Chan said, "We didn't go for the likes of HP, despite being a HP server shop, because it was an expensive solution that seemed like it would lock us in. The problem we saw was that most of the SANs we were being offered were very proprietary, so if you had an HP box you had to have an HP SAN. Also, Fibre Channel equipment costs money and needs training, so it was an expensive solution for us."

The benefits the department has gained are that it now has visibility of all storage from one location and has gained expandable networked storage with greater throughput at half the cost of what it would have spent on expanding its existing DAS.

Chan said, "Our last DAS RAID unit cost £8,000 for 2 TB. The Stormagic device cost about half that for more capacity."

Chan's only complaint with the Stormagic solution is that he will have to buy another licence to expand his networked storage. He said, "Stormagic could improve their product by allowing greater capacity. It has eight 500 MB disks which when RAIDed comes down to 3 TB. It'd be good to be able to expand from that without having to buy another box."

Software-based iSCSI solutions

Stormagic's products are among a flurry of software-based iSCSI solutions emerging as an alternative to hardware-centric products which virtualise heterogenous disk systems into shared storage resources over Ethernet networks. Over the past year, a number of startups have come out of stealth mode, including Open-E and Seanodes, while more established vendors such as Lefthand Networks and Datacore have made inroads into the market for some time.

Such products are particularly suited to smaller businesses because of the cost benefit of only having to pay for software and generic storage hardware. Spend can be cut right down as a spin-off of server consolidation in which users reducing their server count find they can use software-based SAN products to repurpose old boxes as storage devices. Obviously there is a risk that repurposing server hardware will not give the same levels of redundancy that dual controllers, multipath I/O and arrays with RAID protection provides.

The small size of most of the providers in this space can be a blessing or a curse. On the one hand, small vendors seeking to establish a foothold in the market will handhold SME customers to a greater extent than the storage giants. On the downside, these newcomers may themselves become larger companies and lose the personal touch or else disappear.

Read more on Storage fabric, switches and networks