With the price of storage dropping all the time, there is a constant perception from people who don’t deal with it every day that “disk space is cheap”, especially when it comes to developers. The problem is that so called “Enterprise” storage costs are still astronomical compared to what people are used to paying for home storage – even when using SATA disks.
A lot of this extra cost comes from a perceived requirement for the highest available capacity, availability and performance. Achieving all three characteristics is expensive, but if you’re willing to sacrifice one of them then costs start to fall considerably. Lowering requirements on two of the three drops it even more.
One of the teams I work with has a requirement primarily on capacity. Performance and availability are nice, but capacity is the key. We generate gigabytes worth of log files every day, but didn’t have one place to store it all for easy analysis. Just before I joined the team they’d purchased the cheapest “Enterprise” storage system the IT team at the time would allow – it ended up costing in the region of £12k for 12TB of raw storage. That’s £1000 per TB!
In addition to the price, the other problems were accessibility and management of the data and managing growth. This inspired a hunt for something that would provide a cheaper and more flexible solution.
Our requirements were:
- *nix based system. The current storage solution was based on Windows Storage Server, but all our systems and tools for this team are Linux based. Yes, Windows does technically provide things like an NFS server, but fighting with the file system permissions and overall performance are two things that impacted us.
- Cheap to expand. We need to have a clear path to grow the storage in the server easily by simply adding more disks.
- Large filesystems. There’s nothing more wasteful from a storage point of view than having lots of small filesystems. Besides the management overhead, there’s also many wasted blocks lying around un-used.
- Cheap to build. This inevitably means commodity hardware.
- Reasonable availability. We don’t need 99.999% uptime, but would be happy with somewhere in the region of 90%+
- Reasonable performance. Primary access to the data on this machine is via gigabit Ethernet. As long as it can keep up with the network card we’re happy…