Containment: prepare for the all-flash data center.

Containment, in the early days of the flash, was expensive and had been worn out in a few years. Now, the driving price is much lower, and the problem of wear is actually left behind us. Every company should have a full storage data center.
Today, SSD is much faster than any HDD, including random I/O and bandwidth. SSD's capacity is also far beyond HDD.'s 16TB 2.5 inch SSD in the market, and 100TB's 2.5 inch SSD is not far from us. And the best HDD can reach 12TB, for a larger 3.5 inch.

SSD still has a problem of wear and tear, but the manufacturer has improved everything from written electricity to error correction and internal redundancy. Most drives can now survive for about 5 years under a fairly heavy write work load.
Why is the full storage data center?
The price of SSD is still higher than HDD per TB, and one thousand trillion bytes of drive sells for about $250, and HDD is $50. It's the equivalent of comparing Ferrari with a golf cart.
1TB, the $250 SSD is fast. Compared with HDD's negligible 150 thousand IOPS value, SSD can transmit 400 thousand IOPS.SSD, which actually takes the cost of an enterprise class close to 450 HDD, which is much faster than the consumer class HDD. In a full flashing data center, the storage speed is faster and the company's revenue will be more.
Some people may think that the ultra-high speed NVMe SSD (cost more than 250 dollars) will actually replace the enterprise level HDD., but NVMe is only necessary when the application it supports needs to be executed within the range of 2 million IOPS. For many use cases, the SSD of $250 is sufficient.
RAID is decreasing, coupled with the influence of 10+TB driver, the traditional way to ensure data integrity is becoming an obstacle to controller performance bottlenecks and lack of flexibility. The software defined storage will replace the RAID with a small virtual storage device, and the boundaries between the storage and the servers will become blurred.
With the adoption of super fusion devices and the discarding of RAID arrays, dual port drivers are insignificant in the data availability model. This means that SAS is not conducive to the progress of NVMe or SATA.NVMe methods and packaging. The compact flash memory driver is created on the M.2 shape dimension, which is close to the same capacity price close to SATA 2.5 inches.
Where is the flash?
In addition to the innate conservatism of IT personnel, many companies still do not have full flash data centers because of old software. Most applications are written on a single - threaded, single - core computer, on a permanent I/O model. These programs can't get the great benefits of SSD without rewriting.
For example, a HDD based I/O requires a 13 millisecond application that will be sent out and then disconnects to effectively enter the sleep state. Put this together about 20 I/O, which is the permanence of the computer. All of these state switching and idle occupy system overhead.
With SSD, an application can complete a large pile of I/O in a typical 100 microsecond fragment granted by the operating system before switching to another process. The operating system and compiler do not solve these performance problems.
Even so, even without rewriting, the full - memory data center will make the application run faster, with almost no exception. This improvement seems to be in the two to five times, by saving server and equipment costs to pay SSD. to store the large number of suppliers have found that most systems do not use all SSD IOPS. they have applications in the back-end process to compress redundant objects, not slower storage system based on HDD perform well. This reduces the total original capacity required for a given effective capacity, usually five times, mainly in the main memory and the two memory. This is another huge savings, and has a considerable gain in the network load and the delay in loading data to memory.