SATA III or SAS - 6GB/s

VentureRider

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Sep 5, 2011
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Hello Experts!

My current disk subsystem is SCSI-based (U320 controller, LW drives). I'm contemplating moving to SAS drives (6GB), so here is the question:

Based on SATA III reporting 6GB/s throughput, and SAS reporting 6GB/s throughput, which would provide higher sustained throughput?

I beleive I will purchase three drives and RAID them. I have a QNAP NAS, so I'm not really needing additional storage...just FAST OS disk(s).

Thoughts and opinions?
 

VentureRider

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Sep 5, 2011
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LOL...no argument...SSD is the cadillac solution...but that wasn;t the question!

It's the "robustness" of the SSD technology that needs a little more "maturing" before I take that plunge!
 
There is no point in having a RAID0 setup with a NAS device.

Ethernet is roughly 10.5MBytes/second and wi-fi is usually around 3MBytes/second but wi-fi varies by signal strength.

USB2 is limited to no more than 32MBytes/second (not the USB2 limit; it's the SATA->USB converter chip limit).

The only scenario it makes sense to RAID0 an external drive unit is if it is frequently hooked up via SATA or USB3.

Actually, there is another scenario and that's when file size drop very low. Find a benchmark such as HDTUNE for a hard drive and look at file size read vs access speed. If you are transferring very small files on a regular basis and dropping well below 10MBytes/second for a single drive then RAID0 on Ethernet would improve things.

**Keep in mind RAID0 will significantly increase the risk of data loss. A single drive failure loses all data.
 
The same SATA drive connected to a SAS 6 GB/s or a SATA III port will perform the same. A SATA drive has a transfer rate (150 MB/s) that's way lower than SATA II; only SSDs can take advantage of SATA III. If performance is important, then 15K SAS drives are the best solution.