If it was just about adding the latest media type – in this case SSDs based on Triple Level Cell 3D NAND technology – then Dell’s bragging rights for the lowest-cost enterprise flash would last just as long as it took for its flash storage competitors to jump on the TLC bandwagon. In other words, not very long. However Dell’s secret sauce – a virtualized storage array architecture that automatically leverages multiple flash types and hard drives in the same array based on workload goals and usage patterns – gives it a significant advantage over the competition that must offer less elegant, and more expensive, solutions.
“Dell’s unique intelligent data placement strategy allows different types of flash storage — SLC, MLC and TLC — to be efficiently deployed in multiple tier architectures that can be more cost-effective than single tier flash-based arrays,” said Eric Burgener, research director, storage systems, IDC, in a prepared statement. “Dell’s announcement of flash drives built on TLC 3D NAND technology puts them in the storage density lead at 45TB per rack unit for flash-based arrays and drops the dollar per gigabyte cost of enterprise flash storage to roughly the same cost as 15K RPM HDDs — with significantly higher performance. Cost has been the single biggest stumbling block to flash adoption in the data center, and Dell’s announcement of a new lower dollar per gigabyte price point for all-flash configurations enables the use of flash technology across an even greater variety of enterprise workloads.”
Due to ship next month, the Dell Storage SC Series arrays with TLC-based Mainstream Read-Intensive (RI) SSDs offer up to 24x performance improvement and the same price for capacity as 15K hard disk drives, and double the density – 90 terabytes of raw flash capacity per 2U array. The company can now offer SC4020 all-flash mid-tier solutions for as low as $1.66 per gigabyte and as low as $0.58 per gigabyte for typical mid-tier hybrid flash configurations, said Travis Vigil, Executive Director, Dell Storage.
The $1.66/GB claim is based on an SC4020 with the raw capacity of (24) 3.8 TB Mainstream RI (TLC 3D NAND) drives. It includes comparing this 2U “all-in-one” solution (which includes dual controllers, core software, installation services and the typical industry 3-year support contract) against the industry’s leading storage vendors’ street price on similar mid-range all-flash arrays over 1TB: Dell (SC4020); EMC (VNX5200; VNX-F5000); HP (3PAR 7200 and 7200c); NetApp (FAS2520); IBM (V5000); Pure Storage (FA-450); and HDS (HUS110).
The numbers are misleading, adds Vigil, however, which weights the advantage even more in Dell’s favor. The $1.66/Gb price is based on Dell’s raw numbers compared with the competitors’ deduped numbers. When you add dedupe, you get the $0.58/Gb figure, he said.
“Cost is far and away the number one barrier that we’ve seen,” said Vigil, but Dell is addressing another critical pain point, notes storage guru George Crump. An ongoing concern about flash storage is its endurance, he stated in his Dell TLC briefing note.
‘The concern with TLC/3D NAND has been durability. More bits per cell means that cell should wear out faster but again in the all-flash array use case this may be a non-issue if that TLC layer is properly used and protected. The simplest way to hide this vulnerability is to front end it with a small but more reliable SLC or MLC tier that acts as a shock absorber.’
This tiering to address durability also reinforces Dell’s cost focus, he added. ‘The addition of TLC as a supported tier of storage allows Dell to leverage the strength of the SC storage software and offer a very compelling price point for its users.’
Crump also advises that the ability to mix and match different flash media — Write-intensive (SLC), Premium Read-intensive (MLC) and Mainstream Read-intensive (TLC) – calls into question the value of deduplication and compression. ‘If the storage system provides thin provisioning and writeable snapshots combined with competitive raw capacity price points, one has to wonder if deduplication and compression are now past their prime. At a minimum deduplication technology needs to up its game.’
In a recent blog Dell stated the flash-based array market, consisting of all-flash arrays (AFAs) and hybrid flash arrays (HFAs), will grow to $17.4 billion in revenue by 2018, according to IDC. In addition, parts of the flash-based array market will expand at a 46.1% compound annual growth rate over the next five years.
While flash vendors like Violin Memory are loudly chanting the ‘disk-is-dead’ mantra, the latest figures for the enterprise storage market demonstrate disk is alive and well. Total worldwide enterprise storage systems factory revenue grew 6.8% year over year to nearly $8.8 billion during the first quarter of 2015 (1Q15), while total capacity shipments were up 41.1% (so more disk, less buck).
Crump states that most data centers will likely have two tiers: a flash tier for virtual infrastructures and databases, and a high-capacity, object-based storage system to store the unstructured data set. The data center may never be able to consolidate all data into a single storage system, but the two-tier architecture is the best application of available tools for two vastly different jobs.
Dell saw an immediate uptick in flash sales once they managed to equalize costs between high-end disk (10 and 15k HDDs) and flash, said Vigil. With the latest addition to its storage portfolio, he expects an even bigger movement away from 15k to flash. Ultimately, he believes flash will cannibalize both high and low-end disk.
“We believe that the primary way that storage will be deployed in the future will be in a hybrid configuration with flash and 7.2k.” Dell’s flash evolution has moved from single-digit to 60% attach, and the media that took the biggest hit was 15k, while 7.2k grew. He thinks the new price point will create a new inflection point in terms of flash and will reduce 15k and 10k sales.