The use of Solid State disks in data storage systems a few years ago was considered impractical. The high price, the limited number of rewrite cycles, and the lack of performance needs of most customers made SSDs uninteresting for use as part of a storage system.

To date, the situation has changed dramatically and in many installations we recommend using ssd storage.

Traditional approach

When calculating storage for databases and other performance-intensive applications, they usually started from the real requirements for IOPS. The specified number was divided by the typical number of IOPS that one disk gives (for a 7K HDD - this is ~ 100 IOPS, 10K - ~ 150 IOPS, 15K - ~ 200 IOPS) and, taking into account the error on RAID, the number of disks in the storage system was obtained. Knowing the required number of disks to ensure the required performance, then selected disks of the appropriate size for the client's tasks.

Market changes

SaS 15K drives were the first to lose the competition. To order as part of the storage system, they have not been available from a number of manufacturers for several years, and from which they are still available - they completely lost to the SSD in terms of price / performance, price / quality. The direction of 15K disks is no longer developing, no disc manufacturer is announcing new volumes.

Speed requirements have increased, a typical task has become to ensure performance from 10,000 IOPS and above. Using conventional hard drives, we get large disk installations that cover all capacity requirements and provide only the minimum requirements for read and write operations per second. And this is where SSDs come to the rescue.

Modern approach

In our experience, if a customer needs 5,000 IOPS or more on a block system, a storage system with SSD drives will cost less both when purchased and over the lifetime. With less performance requirements, it also makes sense to consider an SSD - depending on the brand of storage, settings, required additional functionality and service, the All Flash system and in this case it can turn out to be cheaper than on an HDD.

Storage systems built entirely on SSD drives over the past couple of years have become such a mass product that most of the leading manufacturers have already supplemented their entry-level (!) lines with such models.

For intelligent file storage systems with compression, deduplication, archiving, and various optimizations, Class A vendors have already achieved such a high storage density that the effective volume significantly exceeds the raw disk space (for example, according to NetApp, the storage efficiency on All Flash FAS systems reaches four times).

Benefits of SSD Storage

1. Linear performance. The linear performance of SSDs is more than 10 times higher than traditional HDDs.

2. Performance in IOPS. Performance in IOPS SSD is higher than HDD by thousands and tens of thousands of times. At the time of writing, the fastest drive offered by NetApp as part of its systems (OEM Samsung) produces 200,000 IOPS, which is twenty thousand times faster than conventional 7K hard drives.

3. The capacity of a single disk. The volume of the largest SSD available for order as part of the storage system is 15.3 TB. For comparison, the maximum capacity of hdD 2.5" — 1.8 TB, 3.5" — 12 TB.

4. Reliability and durability. Theoretical limits on the number of write operations, because of which it was not recommended to use SSD in storage 10-15 years ago, were not achievable in real operation. Even with prolonged use in high-load environments, according to long-term statistics of manufacturers, SSDs practically do not fail even when the DWPD indicator is exceeded.

5. No vibration. The use of SSD-based systems reduces the requirements for the server room due to the absence of vibration.

6. Cost-effectiveness. If we talk about a block storage system with a performance of more than 5,000 IOPS, the cost of acquiring and owning a system is cheaper than systems with an HDD due to the following factors:
   - The price of the initial purchase. As the global volume of SSD production increases and technology improves, the price per megabyte on solid-state drives decreases by an average of one and a half times per year. At the moment, the cost of purchasing a high-performance storage system on an SSD is already lower than on an HDD with the same IOPS and disk capacity.
   - Compactness. Ssd storage takes up less rack space. At the moment, on an SSD of 2U, you can get 4,800,000 IOPS and 367.2TB of raw capacity.
   – Reduced power consumption and heat dissipation. Due to the use of SSD, the difference in the cost of electricity, UPS provision, cooling for three years of operation reaches half the initial cost of the storage system.
   – The cost of warranty service. Due to the high reliability of solid-state drives, warranty support on the storage system is ~2.5 times cheaper in the first three years of operation, and does not increase in cost in the next few years.

7. Prospects. The maximum volume of one SSD disk doubles in a year, and the cost per terabyte decreases at a rate of about 1.5 times a year. At the moment, the maximum amount of one SSD available for purchase as part of a storage system is 15.3 TB. According to Samsung's roadmap, 32 TB of SSDs will go on sale in 2017, 64 TB in 2018, and 128 TB in 2019.

The development of SSD technology has already reached a level where all working data (databases, virtual machines, etc.) is recommended to be stored on an SSD, and the HDD is used only for archival storage of slow, "unimportant" data.

The volume of sales of systems with conventional disks is kept at about the same level, All Flash systems show an increase of ~ 20-30% per year. By the end of 2017, according to Gartner, in the corporate segment, the volume of revenue from SSD sales will already exceed the volume of HDD.

A number of our customers, after testing All Flash systems in their environment, are gradually abandoning the use of HDDs for business tasks. New systems for the workload are purchased only on SSD drives, and existing storage systems on HDDs are used for archival storage.