SSDs vs SAS Hard Drives

For the longest time, SAS hard drives with 10.000 or 15.000 rounds per minute dominated the sector, but nowadays, SSDs are taking over the market.

Useful background – How does a hard drive operate?

Everybody who is just a little bit invested into IT knows that traditional hard drives are slower than SSDs. But few of them know why that is. Hard drives use moving parts to store data, whereas SSDs use semiconductors, making them much faster. In addition, hard drives consist of several discs coated with tiny magnets, which are read out by a reading-/writing tip. There are two things that can make hard drives slower. On one hand, the tip has to move from the middle to the outside of the plate to read or write data. On the other hand, it has to wait until the fitting part of the disc is below the tip in order to write or read.

Why do these special SAS hard drives exist?

SAS hard drives are designed for high speed use, especially when accessed randomly. But what are the keys to their success? On one hand it’s because they are using the smaller 2,5” standard instead of the common 3,5” standard. As a result, the reading-/writing tip doesn’t have to move long distances to get to the right place on the disc. On the other hand, the number of rounds per minute has been drastically increased. While common 2,5” hard drives rotate at 5400 rpm and 3,5” at 7200 rpm, these special SAS hard drives have a rotation rate of 10.000 to 15.000 rpm. As a result, the access time is shortened. In, addition, access to successive part on the plate is almost twice as fast due to the higher rate of rotation. However, one negative aspect is that the magnetic sectors itself can’t be held as small as on slower spinning hard drives. This limits their capacity to about one Terabyte.

SSDs – a new superior technology

While data has been stored with the help of semiconductors for a long time, it has only been used for 10-15 years for the long-term storage of larger amounts of data. These hard drives are known as SSDs. Unlike traditional hard drives, they have no moving parts at all. This reduces access time, especially when accessed randomly. Modern SSDs can be over 16 times as fast as a traditional hard drive. In addition, they can be read almost infinitely often, only writing makes them wear of. As a result, they’re not only faster, but also more durable than conventional hard drives. Furthermore, they are much more power saving and the lack of moving parts leads to lower heat development as well.

In conclusion, it has to be said that hard drives have been replaced by SSDs in most areas. The only situation in which a hard drive may be the better solution is if you have to store a huge amount of data without reading it out very often. In this case you resort to slower, larger hard drives, although SAS hard drives are about as expensive as SSDs but not even half as fast.

If you are looking for a storage solution for a new server, laptop or computer, we advise you to get normal consumer intended SSDs from a reputable manufacurer.
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