When selecting a hard drive for your server, a drive that can hold more data is better, right? Thats not always the case.
Hard drives are very much like cars. You have your daily commuter, family car, hybrid and the popular roadster. Depending on how the business is going to use the hard drive, their best option will change. While there are slight differences between manufacturers, for our purposes we will consider all manufacturers equal and compare the three major technologies: SSD, SAS and SATA. Solid State Drives are the roadsters of the hard drive world. Unlike your traditional hard disk drives which must spin in order to find data, these drives have no moving parts. According to an AnandTech study, the SSD drives they tested could read data 10-20 times faster than traditional HHDs and could write data five to 10 times faster. There have been studies that show degradation in speed over time, but SSDs are still much faster even after accounting for a slowdown. Without moving parts, SSDs also use less power than HDDs which will help businesses that require a large number of drives.
The downside is that SSDs cost more and hold less data. Business class SSDs max at around 200GB of storage today.
For large databases or file servers, this can be a deal killer.
Serial Advanced Technology Attachment drives are the exact opposite of the SSDs.
They are typically larger, cheaper, and slower. They are the tractor trailer of hard drive world. While SSDs focus on speed, SATA drives focus on size. You can find business class SATA drives that can hold 3TB of data -- 15 times more than solid state drives. If you were to go to Dell or xByte, you could spend the same amount and get 60 times the storage capacity using SATA drives.
SAS is the happy medium between SSD and SATA. The term SAS is an acronym within an acronym -- Serial Attached SCSI (Small Computer System Interface). You can get almost 1TB of storage per drive and processing speeds twice as fast as SATA drives (according to the same AnandTech study) without the large price tag of SSDs. These are the daily commuters of the hard drive world. They can get you where you want to go without taking too long or costing too much.
Because of this, SAS drives have typically been the most popular for business applications.
When purchasing your server, you will most likely have to standardize one of these technologies, so do an analysis up front as to how its going to be used.
Additionally, consider all of the potential storage growth over the life of that server. While speed of an SSD drive today may be a nice to have, the cost implications may be too great if your data expands too rapidly.
You can now feel confident that you can manage the hard drive showroom floor when buying or upgrading your next server.