The difference between flash memory and disk
Abstract: At present, there are several ways to integrate flash memory into the data center. For example, flash can be stored on the server for optimal performance, as well as a shared store or a cache for physical and virtual server back-end storage. Companies around the world are flexible in combining these approaches to add flash memory to their IT infrastructure.
In the past few years, there has been a lot of controversy and significant changes between flash memory and disk. Now, instead of discussing whether flash memory can be used in enterprises, we are paying more attention to its cost-effectiveness and acceptance as a key building module in modern software-defined data center.
Most of these discussions are related to the cost reduction of NAND flash. As Flash solutions become more cost-effective, companies see a return on investment and the performance they expect from their investments, and naturally they start to switch storage media. Let's take a look at how architecture is innovating in today's data centers.
Flash memory provides significant benefits in terms of both performance improvements and operational cost savings compared with disk. Thanks to no mechanical components, flash memory can transmit exponential data faster. When you no longer need to use several disks for performance, your data center doesn't spend much space in storeing them, so you can save more space for the CPU to actually process your data. In addition, because flash memory does not rotate like a disk, it does not create friction. Therefore, flash memory generates much less heat than the spindle of disk. Less heat means less heat dissipation, and less budget for energy.
At present, there are several ways to integrate flash memory into the data center. For example, flash can be stored on the server for optimal performance, as well as a shared store or a cache for physical and virtual server back-end storage. Companies around the world are flexible in combining these approaches to add flash memory to their IT infrastructure.
The fast speed of flash memory is in part due to the use of NAND. Flash memory moves electrons, not atoms. Moving an electron requires less energy than moving a physical atom, so it can move faster with much less force. As NAND flash becomes cheaper, disk will become a tape-like archive storage layer, the smallest common denominator for high-performance storage space. This is similar to the case when a disk first entered the market, enterprise still used a tape drive to store data backups. Now, some enterprises are still using tape. We hope that disk can occupy the gap in this archiving market as times goes on.
Although moving electronics sound simple, the amount of moving electrons on flash devices is very large. Each electronic represents 0 or 1. It is necessary to require a mature software to ensure that the data stored on these electrons is secure and that the flash device is reliable. While some SSD vendors have made basic adjustments to SAS and SATA protocols to integrate disks into storage systems, leading vendors are committed to system development to optimize the software that controls the flash platform and integrate it into the server. Impressively, the acceleration of application has made a significant difference among enterprises in the information age.
Another aspect of flash memory that deserves attention is its reliability. Just like a hard drive, a flash drive can wear over time. Disk may fail due to mechanical problems, such as motor failure or head damage (where the head contacts with the rotating disk). Flash memory sometimes causes a failure of a NAND unit because of moving electron. The number of invalidate NAND units is increasing with time going on. However, a mature software can manage all NAND units to wear out at the same time. This wear-balancing technology means that drives can retain more space throughout their lifecycle without performance degradation, while helping IT managers predict and plan the life of their flash solutions. In essence, flash memory failure is easier to predict than that of disk.
In fact, there are the physical differences between the two storage media, like flash memory and disk, electrons and atoms, solid state and machinery. These differences are also why flash memory should not be limited by the instructions and protocols of the disk age. Conversely, flash memory should be integrated into a new and durable storage medium, with potential optimized. As companies begin to exploit new directives and protocols for flash memory functions, they will be able to create apps that were difficult to create before by relying on moving electronics.