Flash forward

Mohammed Dualeh, Pure Storage

Mohammed Dualeh, Regional Sales Manager –MENA, Pure Storage, writes about what IT managers ought to know about all-flash storage systems

Although a majority of storage systems installed around the world are still based on hard disks, a recent 451 Research report determined that flash storage is rapidly catching up and is now accepted as mainstream. This is true for the Middle East where IT storage infrastructure is still greenfield and enterprises have an appetite for adopting the latest technologies.

All-Flash storage guarantees higher performance

Although flash is a storage medium by nature, it bears no similarity to hard disk in terms of performance, endurance and generic behaviour. The benefit of hard disks over flash storage, is that they are able to store data at lower costs, per raw gigabyte. But the benefits stop there!

While flash storage enables thousands of IOPS per SSD, hard disks struggle to provide more than one hundred IOPS per HDD. Some argue that this shortcoming of hard disks can be overcome by opting for hybrid arrays (combination of a little flash storage with a large number of disks). However as soon as the hybrid flash tier is bypassed or overrun due to an increase in random access or a change in the datasets, the performance and more importantly the latency, will suffer enormously. This is because the read-write speed of hard disks is very slow (in the double-digit millisecond range).

All-flash arrays on the other hand, can sustain high performance and consistent sub-millisecond latency because there is no tiering layer as all the data is kept on flash storage. The lowest common denominator to performance and latency is the all flash tier.

Asymmetry in read-write processes of flash arrays improves endurance

The performance benefits of flash storage are already well-known; the short latency times and the capability to supply hundreds of thousands of IOPS, ensure that virtual desktop infrastructures (VDIs) respond significantly quicker, virtual server infrastructures (VSIs) can be managed on a more predictable and simpler basis, and databases and business analytics applications can be expedited.

To achieve these performance benefits and to be more reliable and also more affordable, than mechanical disks, flash storage cannot be treated like mechanical hard disks. For example, in case of flash storage, read processes are free and write processes expensive – behavior which is the opposite to that of hard disks. The read and write processes are largely asymmetrical, because it takes a lot more time to delete a flash cell and write it again than to read it. So when designing a storage system based on flash storage, this asymmetry is the key to guaranteeing a predictable, high performance and highly available experience. To extend the life of the flash storage array, you will want to significantly minimize the number of write processes, while not being concerned about read processes.

Data reduction makes flash storage competitive

If you look at the price per gigabyte, despite the rapid drop in price, flash storage still costs more than hard disk storage. State-of-the-art AFAs cancel out this discrepancy by simply reducing the raw capacity required to store the usable and active data.

  1. Data duplication: Ensures that each data block which is stored on the array is unique
  2. Data compression: Reduces the capacity needed to store each of these individual data blocks
  3. Thin provisioning: Combining supporting procedures such as storage reclamation (SCSI t10 UNMAP) and zero or pattern removal, provides thin provisioning to guarantee that storage capacity is used only by active applications and user data, and not by volume managers, formatting, and deleted data.

Flash arrays thus remove everything superfluous which automatically accumulates when storing data on hard disks. All-flash arrays consequently enable companies to speed up their databases in order to reap business and competitive benefits, and to make mobile users happy with the high-speed response of the VDI environment. Flash Storage ensures that cloud environments (in other words VSI environments) are simple to provide and operate, and that even the most demanding business-critical tasks can be executed. It is impossible not to recognize the all-flash advantages for VDI, VSI and Database environments.

The all-flash data centre is coming

Now that the price hurdle has been removed and all-flash storage systems today cost the same as hard disks, it is no surprise that companies are turning their backs on hard disk systems, and making the switch to flash storage. It is only a matter of time before flash is used as volume storage, for example for seismic analyses, design and CAD, Big Data Analytics, or the Internet of Things (IoT).

The analyst group, 451 Research’s view that the drop in prices is an advantage for all-flash systems is another driver for the enablement of the all-flash data centre. Why should companies forgo the simplicity and the operational savings which result from consistently higher performance and lower latency if it doesn’t cost more than traditional disk storage? The next few years will probably answer these question.

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