Is the flash storage business a hype-filled wonderland or is flash-based technology making real inroads into IT?
Flash arrays provide much faster access to data, because of SSD’s lower latency compared to disk drives but they are more expensive to buy. This can be justified by looking at potentially lower total cost of ownership over five years taking into account power, cooling and rack array space uptake.
You could also look at cost per storage transaction if that gets factored into your budget calculations.
New all-flash arrays from startups don’t have the same width and maturity of data management services that traditional-style arrays have. When these existing array architectures have SSDs added to them, with their controller software updated to use the SSDs well, then such hybrid arrays can provide an attractive middle way between slower, all-disk arrays, and costlier and probably faster all-flash arrays lacking data services.
Modern array use of SSDs, and newer SSDs, ensure longer endurance than earlier SSDs, through management to minimise the write rate to individual blocks on flash chips. Flash arrays can provide greater IO rates than disk drive arrays, and do so in in a smaller space, not needing multiple spindles to increase the overall UO rate.
IDC Research Director Eric Burgener said: “Vendors are aggressively flash-optimising their offerings to provide improved performance, longer endurance, higher reliability, and a lower effective cost per gigabyte. The most successful vendors will be those that can make a smooth transition from the traditional, dedicated application model to mixed workload consolidation.”
The main disadvantage of flash, its cost, is being addressed by chip manufacturers and array suppliers. MLC – 2bits/cell – flash is now mainstream and SATA and SAS SSDs using such chips are commonplace. The arrays housing such SSDs add, typically inline, data deduplication and compression to increase their effective capacity.
Flash device controllers have become more efficient and need less excess and hidden capacity to ensure an acceptable drive working life, which lowers SDD cost.
Basically flash and flash-type technologies promise to banish both disk latency and storage array network access latency to history while continuing to decrease flash $/GB cost.
Already flash arrays are taking over the SPC-1 (random IO) and SPC-2 (throughput) storage benchmarks. Fujitsu’s DX600 S3 all-flash array snagged a good SPC-1 benchmark score, beating mid-range array competition in the sheer IOPS stakes, recording 320,206.35, and coming second to a 3PAR 7400 with its $1.54/IOPS cost – based on list pricing.
Suppliers of all-flash arrays are reporting good business. All existing mainstream storage suppliers are reporting double-digit year-on-year quarterly growth in their flash storage businesses.
Monolithic and dual-controller architecture disk and hybrid flash/disk arrays from Dell, EMC, HP, IBM and NetApp are showing declining or flat revenues while all-flash arrays from these suppliers are growing at significant double-digit rates year-on-year and even quarter-on-quarter, such is the demand. The AFA startups, apart from special case Violin, are also seeing strong revenue growth.
All-flash array supplier Pure Storage has reported beat-the street quarters while Nimble Storage, with its hybrid arrays, grew far less than expected in its latest quarter, widely ascribed to its lack of an all-flash offering.
The conclusion is that there has been huge latent demand for faster access to storage, driven by server virtualisation and multi-socket, multi-core CPUs increasing the IO capacity of servers. But storage arrays couldn’t satisfy it, and the servers and their running applications had to endure IO waits while the storage arrays struggled to keep up.
Having all-flash arrays means that the server’s potential is unleashed and puts compute and IO back in balance. And having all-flash and hybrid arrays and the disk array estate share the same management facilities and data services means that customers’ data centre management facilities are not overstretched in coping with the newer flash storage systems and sub-systems.
Customers are steadily moving latency-sensitive workloads to all-flash arrays, because the effective $/GB cost of flash, after data reduction, is now at or below 15K rpm disk drive costs and approaching 10K rpm drive costs. Once power, cooling and rack space savings are added in, the total cost of ownership of flash arrays can be significantly less than that of traditional arrays.
We’re not seeing a frantic rush to flash, rather a strengthening trend which will cumulatively cut into traditional array sales more and more over the next few years.
As ever IT choices need to be made in a balanced way and we can be glad that, today, we have more choices than before when it was just disk or tape. Now we have all-flash, hybrid flash and tiers of disk, all-disk, tape and the cloud. It means we can apply storage in a more granular way to workloads, resulting in better balanced and more cost-effective systems. Thank flash for that. ®
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