Differences between SAS and SATA hard drives

SASAndSATAHard Disk differences

As you know, like ata, SCSI is a parallel technology that can connect multiple devices through their respective data channels. Like ata, SCSI is also evolving towards Serial technology, which is SAS (Serial Attached SCSI ).

In short, SAS is a new generation of SCSI, which includes some improvements, such as higher transmission speed, better scalability and reliability. Some people think that SAS is a technology that integrates the advantages of SCSI and Serial ATA. In fact, SAS uses the same connector type as SATA, which means it is difficult to identify the drive, but it can help reduce manufacturing costs. In addition, it helps administrators mix and match drive types for different applications as needed.

Since the SCSI technology is so dynamic, why do we need to make changes from parallel to serial? Simply put, the old parallel technology can no longer improve performance. Therefore, the adjustment from parallel to serial technology emerged. SAS provides point-to-point, serial, and manageable storage solutions for storage administrators.

Comparison of SAS specifications

When talking about SAS, it is difficult to compare it with the current SATA standard. The original SAS standard provides a data transmission speed of 300 MB/S or 3 GB/second, And the SATA standard speed can only reach 150 Mb/s. The SATA-II (also known as the SATA-IO) increases the transmission speed to 300 MB/S, making it closer to the current SAS. However, in the next generation of SAS specifications planned to be released next year, the speed has increased to 600 Mb/s, leaving SATA far behind. SAS is expected to eventually reach a speed of 1200 Mb/s. This is so fast!

There are many other differences between SATA and SAS. Simply put, all these differences make scsi a better technology and a better choice than ATA for enterprises. SCSI commands are very powerful and have been used in important applications for decades. SCSI includes features such as command sorting, which enables the Controller to execute commands in the most efficient order to improve performance. In a SCSI system, a dedicated controller is used to process data streams between a disk system and a computer. In most SATA systems, the CPU is used to complete this task, which means that this process may be used to manage storage, such as running databases.

Like the old SCSI and SATA technologies, SAS supports hot swapping of disks, which is very important for environments with high availability requirements. In addition, SAS is a completely two-way system, while SATA inherits the features of IDE and is a semi-bidirectional communication system. Therefore, the throughput of the SAS system can be twice that of a similar SATA system. In addition, few SATA drives can reach 7200 rpms, and many vendors are or are planning to provide ephemeral rpm and 15000 RPMs disks, which also means increased disk system speed.

Another key difference between SATA and SAS is the cost. Similar to ATA and SCSI, Sata and SAS disks differ greatly in price. SATA disks are cheaper than SAS disks. However, many enterprises will still use SAS in their data centers for anti-attack storage and additional storage functions. As described above, this also makes sense.

Since SATA and SAS driver connectors are pin-compatible, their cables seem to be similar. However, SAS cables can be 6 meters long, six times the SATA cable length limit (1 meter. As mentioned earlier, the cable terminals are the same.

In addition to speed differences, SAS has a very prominent advantage over SCSI. In SCSI technology, different types of devices are connected into a chain, and all devices run at the slowest speed. In SAS technology, this is no longer the case. Even for different types of devices, each device can run at its own speed. When it comes to multi-device connections, SAS allows up to 128 devices to be connected simultaneously. By using the extenders, this number can increase to 16,000, this allows SAS to easily meet the needs of even the largest data center. In addition, the SAS disk can process requests from multiple SAS controllers, which further enhances its scalability.

However, there are still some similarities between SATA and SAS. If we compare the original performance of the data center, SAS is undoubtedly the winner. SATA and SAS are complementary technologies. Sata is especially suitable for desktop computers or short-term storage, and is also very suitable for small enterprises for internal storage requirements. On the other hand, SAS has taken over the SCSI flag and has developed well in the enterprise field.

 

Differences between SAS and SATA hard drives