input/output operations per second (IOPS)
Input/Output Operations Per Second (IOPS) is a characteristic value for the data rate at which data is transferred between the processor and the input and output units. It is the data throughput with which the data is transferred to interfaces of the storage media, among other things. The IOPS value is specified as the number of inputs and outputs per second. It applies equally to all storage media, for hard disks, flash memory, hard disks( HDD) and solid state drives( SSD) through to tape drives.
Since the data rates of storage media are different when writing and reading, a distinction is made in the IOPS values between the IOPS input values and IOPS output values and the average IOPS value.
The IOPS performance values for hard disks are specified as a dimensionless number. The higher the number, the more input/output operations can be performed per unit of time. For hard disks, the IOPS value can be a single- digit number and can be up to several hundred operations per second, depending on the number of revolutions of the hard disks. For solid-state drives (SSD), the IOPS value is several hundred thousand, even up to a million operations per second and above, which the drive and its controller can process. This is also due to fast PCI Express interfaces for the solid state disk.
The IOPS value depends on whether the data is read in or read out. In addition, latency is affected by the nominal propagation speed( NVP) of the transfer media and the printed circuit boards, and depends on the length of the transfer path between the server and the data center, which may be some distance away. In addition to the delay times in the active network components, the response times of the memory cells are also included in the consideration.