Purchasing Guide of Large-capacity SSD
Purchasing Guide of Large-capacity SSD
Large-capacity solid-state drives (SSD) are amazing. Many models of them are now coming into the market. Not long ago, a 1 TB ordinary hard disk (HDD) was still big news, whereas now the SSD is developing greatly and is about to usher in the 32 TB.
There are already many large-capacity SSDs on the market. Here are a few of the mainstream options.
Samsung offers a wide range of SSDs. For example, the PM1725 is a 6.4 TB SSD with sequential read speeds of up to 2000 MB/s and random read operations of up to 120k IOPS. Like SSDs made by most enterprise, SSD of Samsung also uses NAND flash memory as a storage medium, using the controller as an interface to the host system to map bad blocks of data, cache read/write data, and perform error checking and correction (ECC). Samsung is also launching the latest products to test the limits of SSD technology, and the first batch of new products will be launched this quarter.
"With our fourth-generation V-NAND technology, we can offer differentiated value in terms of high-capacity, high-performance and compact products," said Young-Hyun Jun, president of Samsung's memory business.
It is said that V-NAND vertically stacked memory cell arrays rises 30% compared with previous generation technologies, which makes it a 64-layer three-level cell flash. Therefore, the System-on-Chip density is increased to 512 Gb, and the input and output speed to 800 Mbps. 512 V-NAND chips are stacked on 16 layers to form a 1 TB package, while a 2.5-inch SSD contains 32 such packages.
Micron's interpretation of the market is that the emergence of high-capacity SSDs is due to the need for companies to upgrade their old IT infrastructure for greater flexibility. Frame-based arrays (10K and 15K HDD stuffed with a single bracket) are gradually replaced by solid-state storage.
"Enterprise organizations are taking the necessary steps to separate more active application storage from traditional storage networks. They are using direct-attached storage (DAS) approach which allows companies to access and leverage data more quickly, giving them the flexibility and insight that they need to succeed," said Scott Shadley, chief technology expert at Micron said:
Micron has always firmly supported new interface technologies (such as NVMe) to help the system enter the fast-moving, high-efficiency line of high-capacity drives. For example, the Micron 9100 PCIe NVMe SSD is designed to provide flexibility and scale for demanding data center workloads. The basic idea is to make non-volatile memory as close as possible to the processor, which is said to be up to 10 times faster than a single enterprise SATA SSD. It offers 3.2TB of storage capacity in models of both half-height and half-length (HHHL) and 2.5-inch.
Micron believes that the highest-capacity SSDs in the highest-end series are suitable for many applications, but not for all applications.
Shadley said: "The initial cost of switching to SSD is not very high. Due to performance, power consumption and total footprint, it can actually save more money in the long run. High-capacity SSD is to support content sharing, namely Cloud services (such as video and media streaming) as well as active archiving applications (highly sensitive information is not just covered), both of which are carefully designed.” But he adds that for read-intensive workloads, you need moderate durability to provide users with consistent data throughput to ensure fast reading, listening, or viewing of the requested information.
“Because of the advent of 3D NAND, a single SSD has reached the cost sensitivity and capacity thresholds previously achieved by HDDs,” said Shadley.
HGST of Western Digital Ultrastar SN100 SSD series combines capacity and performance. It targets cloud systems, hyperscale systems, and enterprise hyper-converged systems. Available in 2.5-inch or U.2 styles, the Ultrastar SN100 uses PCIe and NVMe drivers to ensure low latency even under heavy loads. Its capacity is 3.2 TB.
"The Ultrastar SN100 PCIe NVMe SSD performs particularly well when dealing with mixed read/write workloads (up to 310K IOPS performance) The SN100 is often used by customers with large scale-out databases such as MySQL, Cassandra, MongoDB, or Hadoop HDFS, because these databases favor devices in the server rather than traditional network-based SAN or NAS storage," said Walter Hinton, Head of Customer and Enterprise Solutions Marketing at Western Digital.
Although the SN100 is one of the high-density SSDs on the market, Western Digital does not consider it a replacement for HDD. In fact, it is part of a layered architecture used by most hyperscale/cloud/telecommunications companies to handle the largest number of online transaction processing (OLTP) or online analytical processing (OLAP) data for quick insight to make a decision. In this case, the vast majority of data is stored in the data lake or archive system for a long time.
"For database applications, you should consider the IOPS-to-GB ratio in order to choose a large-capacity SSD or a performance-optimized SSD, or even a layered architecture. SSD performance and capacity have many grades, the total cost of ownership (TCO) is often different," said Hinton.
Storage manufacturer OEM is deploying them to the arrays though disk and flash manufacturers including Western Digital, Samsung and Micron are producing high-capacity SSDs. For example, the NetApp all-flash FAS array with the ONTAP operating system is said to provide high performance, as well as data efficiency to maximize the actual capacity of a large 15 TB SSD. It has 4:1 data efficiency, advanced data management and data protection.
There are also many high-capacity SSDs on the market from leading storage vendors and flash array vendors, which includes followings:
HPE 3PAR StoreServ all-flash storage products come in a variety of SSDs from 400 GB to 15.36 TB SSD. Although the overall IOPS per GP decreases with the increase of capacity in SSD, the overall delay remains constant in large-scale environments. Thus, IOPs are still 15 times denser than HDD even it’s 15.36 TB with large capacity. In addition, the total reconstruction time is much less than HDD.
"We have noticed that our products are quickly recognized by customers after we adopt newer technologies and larger capacity in these SSDs. Thanks to technology development to bring us the density advantages and the cost advantages of these high-density hard drives," said Ivan Iannaccone, director of product management at HPE 3PAR.
From HPE's view, a larger SSD is only reasonable if it is capable of handling large-capacity SSD. For this reason, HPE has invented technologies including Adaptive Sparing and Express Layout to help SSD with arrays process flash memory on a large scale. Adaptive capacity saving is a storage virtualization technology that allows excess capacity to be used as spare capacity, which allows the storage system to survive a component failure. Similarly, Express Layout is another storage virtualization technology that adds more control over where data is stored and how it is stored.