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Enhancing I/O density
In cases where greater performance is required, but needs aren’t so extreme, using SSD more as cache than traditional storage may offer tremendous value. There are three ways to implement SSD in this manner:
- Auto-tiering with array-based SSD. Automated tiering available in enterprise-class arrays keeps data in the same array, but puts the data blocks requiring the most I/O on solid-state storage. This approach can blend spinning disk and SSD for selected applications and increase overall array performance.
- Network-based acceleration appliances. Appliances from the likes of Alacritech, Avere Systems and GridIron can offer shared solid-state caching that can be used by many applications, servers and storage systems. The types of acceleration may be limited (sometimes read only) and may make some fabrics slightly more complex, but these products are worth a look if your acceleration needs are widespread.
- Server-based SSD caching. Server-based accelerators temporarily cache server I/O on internal SSD to help reduce the amount and burstiness of I/Os transacted against an array, and without changing where data is permanently stored. This approach can be very economical and yields notable results when there are particular servers and applications that demand more I/O than others.
in hybrid arrays
The latest hybrid storage arrays offer a combination of solid-state and spinning disk within an array that achieves performance that goes beyond that realized with auto-tiering. SSD isn’t a bolt-on feature with these systems; it’s an integral part of the I/O data path. That architectural approach can optimize storage array capabilities tremendously, so anyone considering a new storage array should carefully consider a hybrid system. These systems provide plenty of performance for reasonably sized active data sets, and simultaneously de-duplicate, compress and tier data onto hard disks. That adds up to SSD performance at a $/GB rate competitive with traditional arrays. Vendors like NexGen, Nimble Storage and StorSimple are in this category, and a number of them have enhanced their products with high-value features like cloud integration.
Meet your needs and keep an eye on the technology
In the long run, it will become clearer that each of these technologies meets a distinct set of needs, and we’ll see the categories and types of products become more distinct.
But whatever route you take now, you should keep an eye on this fast-evolving market segment. With the move to solid-state, there’s more room for software innovation and vendors will likely try to cross the boundaries between the product categories to help broaden their prospective markets. Pure solid-state storage vendors will attempt to introduce uniquely powerful capacity optimization technologies to make their limited capacities as effective as hybrid storage systems. Hybrid storage vendors will try to scale and hone their data placement capabilities to rival the wire-saturating I/O performance of the pure solid-state guys. But by clearly defining your needs and goals, you’ll be able to make the right choice that will meet current needs and serve you well in the future.
BIO: Jeff Boles is a senior analyst at Taneja Group.
This was first published in September 2012