Flash is Ready for More WritesMarch 21, 2013 No Comments
By and large, datacenters have aggressively jumped on the flash-storage bandwagon and have ditched archaic hard disk data storage devices. The problem is that many organizations focus on the significant read functions of these high-speed drives, and haven’t spent too much time considering the write limitations of SSDs. To be clear, these limitations are fairly miniscule in the grand scheme of things, as they can be worked around. But at the very least, especially if you’re new to the solid state storage game, you’ll need to understand these limitations.
The Complicated Relationship Between SSDs and DRAM
The significant limitation that SSDs face has to do with the amount of writes they’re able to perform. In fact, the bulk of today’s SSD drives can only perform a finite number of writes before they will fail completely. To extend the life of these SSDs, all data is stored and written inside the DRAM. Arguably, some of the workarounds for this problem are either not cost effective, or they dramatically reduce the drive’s performance over a long period of time.
The Beauty of Over-Provisioning
For MLC-powered flash drives, this is among the most common workarounds for the significant data write problems facing flash storage devices. This is where more flash storage capacity is put into the device than is actually reported to the server’s operating system. This allows data to spread across multiple flash cells, while removing bad blocks of data and replacing them with good blocks. This goes a long way to increase the overall lifespan of a flash drive – sometimes by upwards of 25 percent.
Solving the DRAM Problem
The optimal way to fix this problem is by manipulating the DRAM in a way that organizes data more effectively before the write even reaches the flash component of the drive. The only reason this is possible is because DRAM is much more stable, and even more powerful than the flash technology itself. It doesn’t have many performance issues or limitations.
Solving the SSD Limitation Problem
Still, SSD writes are much more expensive than hard disk writes. Data cannot merely be overwritten. It must be erased completely. The beauty of the flash storage revolution is that companies are designing devices with inexpensive MLC technology. Again, the problem is that these devices can only handle a limited number of writes before they will fail. In response to this problem companies like Pure Storage have developed operating systems that can work around these problems effectively. For instance, Pure Storage’s operating system, Purity, was developed to ensure that these write limitations don’t completely exhaust SSDs. In fact, Pure Storage offers a five-year warranty on all of their hardware, which is virtually unheard of in the enterprise flash-storage space.
If the read/write dilemma has kept your organization from jumping onto the solid state storage bandwagon, it shouldn’t. Yes, there are some limitations to overcome, but as you can see these are small hurdles to get over, and there are more efficient infrastructural data management designs available to help you get over those hurdles quickly and efficiently.
About the author: Dawn Altnam lives and works in the Midwest, and she enjoys following the business tech world. After furthering her education, she has spent some time researching her interests and blogging of her discoveries often. Follow her on Twitter! @DawnAltnam
DATA and ANALYTICS , Fresh Ink, SECURITY