SATA vs SAS Hard Drives on Dedicated Servers

Quick, Simple, and Scalable Dedicated Servers

What Is the Difference Between a SATA Dedicated Server and a SAS Dedicated Server?

Do you want a SATA dedicated server or a SAS dedicated server? Steadfast Networks offers both kinds of drives, but which one is right for you depends on the needs of your business. Will you be targeting more of a consumer market, or do you need your drive to handle lots of critical server applications? Both kinds of drives allow you to send and receive data at the same time, and automatically assign device IDs, rather than forcing you to do it manually. Hot-plugging is available on both. So what, really, is the difference?

Physically, not a whole lot. The pinout is the same on both for data and for power connections, but SATA physically separates the two connectors, while they are merged for SAS. This means that you can attach a SATA drive to a SAS controller, but there’s no way to connect a SAS hard driver to a SATA controller. Performance specs are relatively similar, too. Both SATA and SAS have a 3 or 6 Gbit/sec maximum bandwidth for each port, but that is not generally a bottleneck on hard drives.

In general, the real difference is that SAS drives are more versatile and better for critical, higher-end functions needed for server applications, whereas SATA drives are better suited for personal computers. Specific differences?

SAS drives support rotational speeds of up to 15,000 RPM, comapred to a standard 7200RPM SATA drive. This rotational speed difference is often the biggest difference and means that the latency for processing transactions is significantly lower on a SAS drive, most SATA drives have an average latency of around 4.2ms while SAS drives can be around 2ms. This results in SAS drives being quicker to respond and then also being able to perform more input/output operations per second (IOPS). If you're really pushing disk IO, this can be a major advantage, but for truly amazing disk IO you can also look at Solid State Drives.
Basic SATA only contains commands for direct-access storage; SAS, however, uses SCSI, which can go through ATA for increased versatility.
SCSI error-reporting and error-recovery commands on SAS are more functional than those on SATA drives.
Multipath I/O is possible with basic SAS hardware, but not with basic SATA hardware. However, SATA can gain the ability for multipath I/O by using port multipliers that have implemented multipath I/O.
SATA drives use native command queuing, while SAS drives use tagged command queuing.
SAS protocol allows for an SAS domain to have multiple initiators; SATA doesn’t have anything comparable to this.
SAS has a higher signaling voltage, allowing for its use in server backplanes.
The higher SAS signaling voltage means that you can use cables up to 10 meters long, while the length limit for SATA is only 1 meter (or 2 meters for eSATA).

Just from reading this, it would seem that SAS is the better choice, but it’s not quite so simple. As mentioned above, SATA is quite common in the consumer personal computer market. If you just need a good, basic server, it works fantastically. And one other thing – it’s significantly cheaper than SAS, especially on a cost per GB basis. Unless you’re looking to create an advanced server environment, most people probably don’t need SAS drives.

How to get a SATA Dedicated Server or SAS Dedicated Server from Steadfast Networks

When leasing a dedicated server from Steadfast Networks, you can talk to our knowledgeable representatives about your needs, and they’ll help you determine what kind of drive is best for you. Our servers with basic management start at $79.95/month, and drive upgrades are available at an additional monthly cost.

SATA drives:

500 GB Hard Drive - $15 per month
1 TB Hard Drive - $30 per month
2 TB Hard Drive - $40 per month
3 TB Hard Drive - $50 per month
74 GB Raptor SATA 10k RPM Hard Drive - $15 per month

SAS drives:

74GB 15k RPM Hard Drive - $25 per month
146GB 15k RPM Hard Drive - $30 per month
300GB 15k RPM Hard Drive - $50 per month
600GB 15k RPM Hard Drive - $75 per month

Those interested in the increased reliability that RAID brings may also add that functionality:

2 Port SATA Hardware RAID - $20 per month
SAS/SATA Hardware RAID - $50 per month

SATA and SAS Drive Technical Requirements

Both types of drives are compatible with Mac OS X, Linux, and most Windows operating systems – and since Steadfast Networks will be managing the install for you, you can rest assured that we will meet or exceed any technical requirements for specific kinds of drives.

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