Solid-state drives (SSDs) are devices that do not have spinning disks. Today's solid-state technologies, such as DRAM and NAND flash, provide faster data access, are more efficient, and have a smaller footprint than traditional spinning disks. The data center uses solid-state technologies in many form factors: in-server, all flash arrays, all flash appliances, and mixed with traditional HDD arrays. Each form factor offers a different value proposition. SSDs also have many connectivity types: PCIe, FC, SATA, and SAS.
Due to the current cost per gigabyte of SSD devices, the best value of SSDs is not as high capacity storage devices. The benefit of adopting SSDs is to improve performance and reduce the cost per I/O per second (IOPS). Data efficiency and placement is critical to maximizing the returns on any data center's investment in solid state.
The SmartIO feature of Storage Foundation and High Availability Solutions (SFHA Solutions) enables data efficiency on your SSDs through I/O caching. Using SmartIO to improve efficiency, you can optimize the cost per IOPS. SmartIO does not require in-depth knowledge of the hardware technologies underneath. SmartIO uses advanced, customizable heuristics to determine what data to cache and how that data gets removed from the cache. The heuristics take advantage of SFHA Solutions' knowledge of the characteristics of the workload.
SmartIO uses a cache area on the target device or devices. The cache area is the storage space that SmartIO uses to store the cached data and the metadata about the cached data. The type of the cache area determines whether it supports VxFS caching or VxVM caching. To start using SmartIO, you can create a cache area with a single command, while the application is online.
When the application issues an I/O request, SmartIO checks to see if the I/O can be serviced from the cache. As applications access data from the underlying volumes or file systems, certain data is moved to the cache based on the internal heuristics. Subsequent I/Os are processed from the cache.
SmartIO supports read and write caching for the VxFS file systems that are mounted on VxVM volumes, in several caching modes and configurations. SmartIO also supports block-level read caching for applications running on VxVM volumes.