Rob's Blog

Building an iSCSI SAN on the cheap

The last few days I’ve been planning my company’s IT strategy for the next year with our new financial year looming. Having just started with this company, I’ve walked into a role where most of the servers run either on non-server hardware or are many, many years old. However, I don’t really have the budget to replace them all. Enter virtualisation…

The first part of this project is the storage layer. The cheapest solutions come in at around £10k for my needs – dual redundant PSUs, dual redundant storage processors and 7 x 500Gb disks – 4 for 1Tb of RAID 10 storage for databases (although EMC continually claim RAID 5 performance to be almost as good as RAID 10, I don’t believe them), 2 for 1Tb of RAID 0 for log files and one hot spare. Solutions from Dell|EMC, HP and IBM are all around the same price point.

Fortunately, if you don’t have a spare £10k in your pocket, a SAN solution can be reduced in price dramatically. Sure, you won’t get all the nice features afforded to you by an EMC, HP or IBM SAN, but you’ll do it on the cheap.

This is where iSCSI comes in. Traditionally, SANs have been the preserve of big businesses who could afford miles of fibre cabling and highly expensive Fibre Channel hard disks. Nowadays, small businesses can get in on the act too – lower priced systems, utilising iSCSI (that’s SCSI over IP to those who don’t know) and cheaper SATA disks are cropping up from a number of providers, including EMC and Promise. These providers are really lowering the entry point for anyone looking to get into SAN technology. Believe me, when you’ve worked with a SAN and the flexibility it can afford you, you won’t want to go back.

Still too expensive? Looking to set up an iSCSI network at home? The beauty of iSCSI is it’s standardisation. It runs over IP so all you really need is any piece of hardware with a NIC and some hard disks to start plaing with iSCSI. There’s a nice article on how to set up a Linux-based iSCSI target (hosts – the servers providing the services – are called targets in iSCSI lingo, whereas clients – machines using these services – are called initiators) on Red Hat’s Fedora Core 4 over here. Or, if you’re much more of a Windows person, then there’s a commercial product from String Bean Software (and I think I’m correct in saying that Microsoft have now acquired String Bean) that does the same thing – you can find that here.

There’s also a great way to start playing with iSCSI if you don’t understand it – virtualisation. Yes, I’m a big fan of virtualisation – I love playing with new stuff but I don’t want to have loads of PC’s or servers knocking around the place – so virtualisation is the way forward. In this case, you can download a pre-built iSCSI target from the VMware Technology Network, where someone has very kindly done all the hard work of building an iSCSI target for you.

Now I’m not recommending you do this in a live business environment. After all, you’re not getting any of the nice management software that comes with a SAN solution, nor do you get full resiliency built into your solution. However, if you need to get some storage sharing into your business but don’t have the budget this is the perfect solution.

Next time I’ll be talking about the second part of this project and my favourite topic at the moment, virtualisation!

This entry was posted on Saturday, February 24th, 2007 at 9:55 am and is filed under Storage Area Networking. Find similar posts by selecting any of the following tags: iscsi, san, Virtualisation. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.