The use of solid state technology in the form of NAND flash for storage systems changes the way we need to evaluate storage. While it brings power, space, and reliability advantages, the main reason for using solid state is performance – it accelerates applications.
Still, storage vendors often characterize their flash systems in ways more fit for spinning disk. The numbers usually quoted for storage systems are:
IOPS – The number of I/Os per second that a storage system can do.
Bandwidth – The measure of throughput for sustained data transfer as an MBps or GBps number. Bandwidth measures are important when dealing with a high volume of data. The data transfer rate is dependent on the size of the data transferred (block size) and the overhead processing between each block. Infrastructure options — including the fabric and the network reliability to ensure transfer completions without needed retries — are also considerations.
Latency – This represents the time required for an I/O operation to complete.