Lovely woman
Jay's new songs again, I also grew up listening to jay's new song Eva ~! Jay new song "waiting for your class once released," is a piece of, I also have to think of my senior year, the topic of today, let's talk about women ~! Lovely woman has four: or beautiful, or tender, or smart, or,,,,, bad you can't ~!
CDN function is the cache user's content and quickly to the nearest service, is the most important parts of the storage hardware, storage as we miss lovely woman inside ~!
Beautiful let me face red lovely woman
My fair lady, gentleman good qiu! The beautiful women!" Memory is beauty ", worthy! Every time we will be the customer asks, content is hit, hit is memory? Memory as the fastest storage hardware, the hottest content is stored in the CDN server, memory hits means content can fast high throughput provides content services, however, because the memory is expensive, and in proportion to the server's storage hardware, they will not too high, the average content of 256 g is it to the server, so how to better will allow hot spot content into memory, the cold scheduling to hard disk, the CDN is a timeless topic,
Gently let I love the lovely woman
Gentle woman, let us love, we love money ah ~! (love) SSD beauty, really very gentleness, generally we only used in the video server or small file services, because it is second only to the speed of memory, and a SSD capacity can already go to the level of TB, but somehow the knife down, or expensive said ~! I looked at it and jingdong quotation, memory per GB to 80-100 yuan, per GB SSD is about 3-5 yuan, but as long as 0.2 ~ 0.3 yuan/GB sata hard disk. See during the huge price gap, the middle is not one or two orders of magnitude of poor ah ~!
Smart let I touched of lovely woman
Intelligent woman let us moved, because cheap ah ~! SATA beauty touched, moved, with its cheap, let us to tears, brothers let match, as long as the server disk enough, are put on the large capacity SATA disk, 8 and 12 TB gradually into the mainstream, "clear water gives lotus, natural go vulture act the role ofing," we love the) large SATA disk, but little woman run fast, an order of magnitude slower than the SSD, speed and price is proportional to the ah ~!

Mind let me crazy of lovely woman
Badly lovely goddess ~ ~ ~ ~, the SAS disk, because its speed is very fast, is generally more than 10000 revolutions per second, common mainstream SAS disk all at 15000 RPM, speed fast mean IOPS will also increase, but the small make up or don't think price is too high,
According to the following theoretical calculation method of maximum IOPS
IOPS=1000 ms/(seek time + rotation delay),
7200 RPM disk IOPS=1000/(9 + 4.17)=76 IOPS
10000 RPM disk IOPS=1000/(6 + 3)=111 IOPS
15000 RPM disk IOPS=1000/(4 + 2)=166 IOPS
7200 RPM SATA disk, actually also is slower than the SAS half speed, the price is up to 0.8 0.9 yuan per GB, personal feel is not a reasonable business ~! So bad, we still stay at a respectful distance from sb ~!