SAS Performance at SATA Pricing: Cost-Effective SAS RAID Controller

INTRODUCTION

What is important when shopping for hard drives is the storage space, rotational speed, amount of cache, and of course the price. Currently, for desktop computers, 7,200 RPM SATA II hard drives are the most common type of storage. For enterprise and business, there is SAS, which stands for Serial Attached SCSI.

Although SAS HDD's are primarly aimed for the enterprise market whose main goal is to achieve the highest performance, the fact that you can find these drives in speeds of up to 15,000 RPM makes them a good candidate for enthusiasts as well. Current desktop SATA HDD's have rotational speed of either 5,400 rpm or 7,200 rpm. For the enthusiasts, SATA drives can be found in speeds up to 10,000 RPM. SAS, on the other hand, can be found commonly at rotational speed of 10,000 RPM and 15,000 RPM.

What determines the performance of any hard drive is the rotational speed, the amount of cache, and the lesser known information, the platter density.  Generally speaking, when shopping for a high performance hard drive, one should look for the highest density per platter (with 320GB/platter being the highest at the moment) and fastest rotational speed. Thus, at 15,000 RPM, SAS hard drives are the performance leader of conventional HDD's and should prove to have the best performance.

Although, Solid State Drives are the talk of the industry for being the replacement of conventional spinning platter disks, the truth is that current Solid State Drives are insanely expensive, the storage capacity is pale compare to the terabytes offered by the SATA, and the write speed is yet to perform on par with mechanical drives. Thus, we are not going to see them to become widely available any time soon, but with technology improvements, we should see them becoming more accessible to enthusiasts and even hitting the mainstream market.

This is where SAS drives come in. Although SAS drives are relatively expensive compared to SATA drives, they are not as expensive as SSD's and are able to offer better performance than SATA with more balanced read and write performance than SSD's. Today, we will be comparing the 15,000 RPM SAS drives running in RAID 0 versus 7,200 RPM SATA drives in RAID 0 to see the performance gains of going with the SAS drives.