In our first entry on 2012 storage trends, we look at an aspect of flash-based storage, not that flash storage is suddenly a trend--it's reality. What is a trend, though, is the move to flash-dependent systems.
Flash-dependent storage systems are systems that are either all-flash or systems where flash plays a critical role in the delivery of data. The first to keep an eye on are flash-only storage systems. These are different than solid date drives (SSDs) or solid-state storage appliances; they are complete storage systems with typically a robust storage feature set like snapshots and replication. They are designed to compete directly with traditional legacy storage systems instead of augment them like other solid-state storage solutions do.
Their big differentiator is that there is no mechanical disk storage in them. To keep costs down, these vendors use technologies like thin provisioning, cloning, and deduplication to reduce the cost per gigabyte concern that you would typically have when considering flash-based media. There is no doubt that the above combination of technologies can drive the cost per gigabyte of flash-based media into the realm of a high-performance 15K RPM hard drive-based system.
There are flash-dependent systems where flash plays a critical role in the delivery of data to the application but still have some form of mechanical storage available to them. These systems are typically using flash as a cache, as we discussed in our article "The Advantages Of Storage System Based Caching" or they're using flash as a primary tier. In both cases flash is designed to augment the use of high-capacity SATA-based mechanical hard disk (HDD) drives instead of lower capacity high-performance SAS-based hard drives. The goal of these systems is to deliver better performance than a storage system configured with high-performance hard drives and no flash, but do so at a lower price point. The combination of HDD and flash allows for a much smaller allocation of memory-based storage which also helps keep prices down.
The key difference is the sensitivity to, or likelihood of, a cache- or memory-based tier miss, which would mean that data has to be retrieved from the mechanical hard drive storage tier. In flash-only systems there is no chance of a miss, but there is a likelihood of a higher cost.
If you are looking for a new high-performance storage system to solve a broad range of application performance problems the flash-only systems certainly warrant strong consideration, especially if the data is not cache friendly. If you need a new storage system but your performance needs are more modest, where an occasional access from a mechanical hard drive storage tier and the resulting lower performance is not an issue for you, than a flash-dependent system may be a better option.
If your current storage solution performs admirably but you need a performance boost for a very specific application set, then one of the more traditional solid-state storage appliances or servers with installed PCIe-based solid-state storage devices may be more appropriate.
In reality we think that most will end up with a combination of server-based caching, typically via a PCIe solid-state storage device and either a flash-only system or flash-dependent system.
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