Dedicated servers comes at higher prices if associated with a system disk with SAS technology. Here we explained the reasons that lead to a different financial offer by the provider, and when you need to choose the SAS compared to the best known format SATA.
When you configure a range of dedicated servers, many domestic and foreign providers allow you to choose the disk system you prefer, proposing among different types of solutions, often summarized in as many acronyms as SATA, SAS (together with NL-SAS) and SSD.
While the SATA and SSD disks are well known (because used in desktop solutions), SAS technology and its derivative NL-SAS, on which we will focus in the following, are not well known and often do not understand the real difference and the benefits that these proposals can be made to dedicated servers, thus justifying a higher cost for different configurations only disks in the system.
The acronym SAS indicates a technology solution designed as an evolution of the ancient SCSI, so that the acronym stands for Serial Attached SCSI. The evolution of serial SCSI format, which has followed in the footsteps of the evolution of disks from the desktop PATA (Parallel ATA) SATA (Serial ATA), with all the benefits that come with it.
SAS drives are therefore designed for enterprise use, and dedicated servers to ensure not only greater speed also due to a greater number of revolutions of the disk per second (disks now it has come to 15 000 RPM with a transfer rate of 12 Gbps ), but are designed to ensure a high level of reliability, because of not only to the technology itself, but also to the electronic components used to build the units, targeted at the enterprise and thus better controlled by the producers.
SAS Dedicated servers are most reliable?
The answer is simple: reliability is the price. A SAS disk has a BER (Bit Error Rate) of 1 in 10 ^ 16 , or you can see a bit error per 10 bits of billiards. The SATA drive has a BER (Bit Error Rate) of 1 in 10 ^ 15, then you have a bit error every pool of bits. As these figures are very large in both cases, for applications in which the correctness of the data is critical (as in applications Enterprise), SAS technology is the most suitable. Similarly, for SAS disks changes the Mean Time Between Failure (MTBF) rising from 1.2 million hours (136 years) of the SATA 1.6 million hours (182 years) of the SAS.
These data, plus a whole host of features that SAS technology guarantees with respect to the SATA data port failover on multiple, multiple hosts, hotplug (officially supported also by the specific SATA), simultaneous data channels and enterprise command queuing, which then make the SAS best choice in all cases in which the budget is not a problem, but we look for the highest possible reliability solutions disks to be associated with functions dedicated servers with mission critical.
To bridge the gap between SATA and SAS, are then come on the market the devices NL-SAS , hybrid solutions between SATA and SAS, with the advantages of SAS and reliability in terms of BER and a MTBF of SATA, while maintaining overall performance better than the latter.
In short, if you configure dedicated servers seeks above all reliability, SAS is the right answer in the choice of system disks, but if you look at the amount of space at a competitive price, then it is right to choose the SATA subsystem.