At present, with the gradual increase in the user for data processing speed requirements and system application has become more and more strong, how to improve infrastructure performance has become the user face a constant challenge. If the whole infrastructure I/O performance can't get a promotion, once can't keep up with the pace of the development of the whole system, then even if is to use more powerful CPU, more high-speed network and more hard disk capacity, and to meet the Compaq Presario C710EL Cpu Fan needs of users, also appears under.
Real cases, our common some users in order to improve system performance, even if the existing server have enough storage capacity, also will be added constantly high speed drive (HDD), or add new server. However, no matter what kind of method, the final result is storage capacity increasing but the utilization rate is lower. At the same time, add new server means to increase the capital and operating costs including operation and maintenance, power supply and cooling costs and room physical space expansion. Therefore, solid state disk (SSD) appear and popularize ease a lot of memory problems, and change the user for storage structure way of thinking.
Compared with HDD speaking, solid-state disk has many advantages, including higher read bandwidth, higher IOPs, better mechanical reliability, higher resistance to impact and earthquake resistance. However, provide the functional characteristics of these benefits at the same time, also brought some inherent limitations, such as the limited capacity and lower flow write bandwidth.
Another limitation of SSD is not like HDD that direct excess write data. On the contrary, it in data write before must first erase the whole target data block - even if only a few bytes change. This process not only to write performance caused negative influence, but also may lead to flash memory medium surface wear uneven, resulting in the hard disk of the early failure.
In order to overcome the problem of unbalanced loss, a lot of SSD technology using loss balance scattered erase operation, in the medium surface evenly to write. Loss balance extended the hard life, but with the passage of IBM Laptop CPU Fan, write performance will also further degradation. Moreover, the cost is much higher than SSD HDD, especially with traditional "cost per GB standard to measure. Many storage experts point out that, in most environments, if not considering potential advantages, with a SSD replace all HDD is unrealistic. However, HDD and SSD hybrid approach provides a high cost efficiency, especially with "every I/O cost" standard or more with green energy saving as the leading "every I/O energy consumption" standard to measure.
Obviously, want to get SSD and HDD advantages, abandon the shortcomings, then we have a new redundancy storage solutions to solve these problems, the SSD and HDD mixed properties and advantages to develop acme. Therefore, the birth of the hybrid RAID on the industry to have the significant influence and significance. Mixed RAID adopted high volume low cost or high performance SATA SAS hard disk and low latency, high IOPs solid state disk, coupled with the perception of SSD RAID control card, by their common form a mixed RAID solution.