For more than 60 years of its existence, the hard drives have decreased considerably in size, but have increased in capacity and speed. And the pinnacle of steel server drives, such as Toshiba MG08. The novelty has impressive volume and long service life even under continuous operation.
Despite its high speed read and write, solid models are much more expensive than traditional solutions. In the consumer segment, the difference is not so noticeable — SSD «system» has become mainstream. But when talking about terabytes, the amount of the check increases dramatically. For several years their price has decreased, but the HDD fell: a niche in the market, they will keep for a long time.
For servers manufacturers produce a separate line of drives with high vibration resistance, reinforced spindles, algorithms of self-diagnosis and an impressive MTBF. One of the novelties of the business line was a series of drives Toshiba MG08 with a maximum capacity of 16 TB. The «Winchester» has retained all the key features of their predecessors.
Reliability. The technology of Conventional Magnetic Recording (CMR) involves a direct write data to tracks of the hard disk across the width of the magnetic head. In comparison with tile record (SMR), when paths are overlapping, this method is inferior in capacity with an equal number of plates, but wins in speed.
SMR solutions when overwriting the files retain the new information on free tracks separately from the original so as not to overwrite the «neighbors.» And the synchronization is carried out in standby mode. As a result of increased access to data and the number of rewrites. The model on the basis of the CMR from this «side effect» did not suffer, therefore they are distinguished by high reliability. The average time between failures 24/7 for a series MG08 is up to 2.5 million hours, and the estimated load of up to 550 TB per year (reading and writing).
To further increase the fault tolerance of the drive helps fill his body up with helium. The gas density is seven times lower than air: this reduces the friction force of the magnetic plate and turbulence, which affects the positioning accuracy of the reading and recording heads. Stated the average surface temperature of the drive — not more than 40°C. Use of helium also allows to place on the spindle more «pancakes» HDD without any loss of reliability. The seal body is made using proprietary laser-welding technology, which prevent leakage of inert gas.
Volume and performance. To increase the density and performance of the drive is called two-dimensional magnetic recording, the TDMR. It allows to reduce the width of the tracks on the plates, as for the accuracy of the read data with «compression» of the cells without interference from their «neighbors» meet two magnetic heads under control of controller with special algorithms.
In the end, a standard 3.5-inch enclosure Toshiba MG08 thickness of 26.1 mm holds 9 plates total capacity of 16 TB. With the growth of the HDD increased the buffer size up to 512 MB. The novelty is presented in two versions — with a SAS interface and bandwidth of 12 Gbps, as well as the traditional SATA (6GB/s). The spindle speed of all modifications is 7200 rpm.
Server drives are not meant to replace high-speed SSD, but for storage, processing and backup of the data replacement it is not expected for a long time. Especially in cloud storages, where reading occurs more often than writing, and the reliability and the price of gigabytes play a major role.
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