Not so long ago, the divide between flash and conventional magnetic hard disk storage was clear: flash delivered levels of performance well beyond the capabilities of hard disk arrays, but couldn’t provide the same capacity at an affordable cost.
Not so long ago, the divide between flash and conventional magnetic hard disk storage was clear: flash delivered levels of performance well beyond the capabilities of hard disk arrays, but couldn’t provide the same capacity at an affordable cost. The only cost-effective way to harness flash’s performance was to position an all-flash array up front of the SAN as a high-speed cache. Or move to hybrid storage arrays, which combined flash and hard-disk storage to improve performance while delivering on capacity and price.
Tikiri Wanduragala, EMEA Senior Consultant at Lenovo says that ‘hybrid storage used to be the intelligent compromise, and the relatively easy upgrade path from legacy technologies helped make it a mainstay for enterprise IT. Now, however, for an increasing number of organisations, its time may be over. That compromise feels increasingly unnecessary, with everything moving in favour of the all-flash vSAN instead.’
The all-flash advantage
Why? For a start, flash storage has reached commodity status and the technology is developing rapidly. In the last few years we’ve seen multi-level cell (MLC) and triple level cell (TLC) NAND technology improving performance, reliability and density, in turn reducing cost. Now 3D NAND technology, where flash cells are stacked in levels 32, 48, 64 or even 72 levels deep, is taking that even further. It allows manufacturers to produce chips with three times the capacity of 2D equivalents – and that will only increase as the technology matures. This will inevitably drive the purchase cost of all-flash vSANs down, even given the need for substantial overhead in MLC and TLC flash to allow for wear and ensure long-term reliability.
Indeed, purchase cost is only one part of the story. Switching from a hybrid storage array to an all-flash vSAN brings a range of TCO benefits. Flash storage uses much less power, requires less cooling and takes up less space than equivalent hard disk storage. In raw watts per terabyte terms we’re talking 8W/TB rather than 80W/TB. Operating costs go down so a lot more storage can fit into the same rack space – which is great news for those consolidating infrastructure.
In terms of performance, all-flash vSAN is a no-brainer. A recent test of all-flash vSAN vs. hybrid vSAN saw a database performance advantage of 49%. This, combined with intelligent reduplication, compression and thin provisioning storage at the OS and application layers, makes all-flash vSAN a smarter, faster and more cost-effective choice for virtual desktop infrastructure (VDI), server virtualisation and database workloads. In each of these scenarios, the speed of all-flash makes it much more efficient when working in real-time on large datasets.
As Wanduragala explains, ‘the barriers that kept enterprises from adopting all-flash vSAN are disappearing fast. As purchase costs continue to slide and the TCO advantages become clearer, the raw performance of all-flash vSAN will give organisations the kind of immediate data access that’s critical to building a competitive edge. All-flash vSAN is ready to come down into the mainstream, bringing high performance, non-stop availability and reduced TCO’.
The all-flash era has arrived
Flash used to be too expensive to bear the grunt work of enterprise storage, but as purchase costs come down and the TCO benefits ramp up, we’re reaching the tipping point where hybrid storage stops making sense. Performance-driven applications will be the first to go all-flash, but expect mainstream business apps to jump on the bandwagon as hybrid storage loses its cost advantage. For flexible, effective storage to power the business of the future, all-flash is becoming the only serious contender.