Performance Improvement by having same SATA Versions?

[ds679]

I have two Un-Raid setups...have been enjoying them for years!

 

I'm thinking about (simple) ways to optimize/improve their performance and one 'issue' seems to strike me and I can't seem to find a clear answer on the Forums (if there  is one, please reply with the link...thanks!).

 

On my two systems, I have some drives that have SATA Version 2.6 (running at 3.0 Gb/s) and some that are SATA Version 3.*+ (running at SATA 3.0, 6.0 Gb/s (current: 3.0 Gb/s)).

 

Question:  If I were to move/replace drives to ensure that all are SATA Version 3.0*+; would the system performance improve?  Would they all be running at 6.0 Gb/s and not be downgraded?

 

Thanks in advance,

 

-dave

[garycase]

The simple answer is No ... there's no reason to replace your SATA-II drives with SATA-III drives.

 

First, unless a SATA-III drive is connected to a SATA-III controller, it will simply run at the speed of the slower controller (whether SATA-I or SATA-II).    But most significantly, NO modern rotating platter drive can sustain transfer rates faster than SATA-II, so there's virtually NO benefit from using SATA-III for those drives.

 

There IS a VERY tiny % of transfers that will be helped -- the transfers between the drive's buffer and the PC => but that's a VERY small % of disk activity, particularly when you're steaming media.  And for things like parity checks and drive rebuilds, there's NO difference in the performance, since those speeds are entirely dependent on the sustained transfer rates of the drives.

 

SATA-III DOES make a difference if you're using SSDs ... i.e. for your cache (or cache pool).  But for normal drives, there's no reason to make the changes you asked about.

 

[ds679]

Hi Gary - thanks for the quick follow-up...and this probably answers why I wasn't able to find much information about it.  I just felt like, "Dang, they are saying 6.0 Gb/s...but only running at 3.0 Gb/s".  It seemed like there might be a way to 'double' performance!?

 

Either way, do you know if/when a new 'performance' guide might be written for the 6.0+ Version?  And/or link to the old one that might still be relevant?

 

Thanks in advance,

 

=-dave

[SSD]

Imagine you are driving your 2002 Honda Civic on a road with the speed limit of 150 miles per hour. You start buzzing down the road and realized that at about 97 miles per hour she's got nothing left to give. You are maxed out! Suddenly the speed limit changes to 300 miles per hour. How much faster are you going to go now?

 

Now imagine that you are flying an airplane with those same speed limits.

 

In this analogy, the Civic is a rotating drive, the airplane is an SSD.

[RussellinSacto]

BJP,

 

Just an FYI - most single engine aircraft (non-jet) can't exceed much over 200 MPH.

 

If, when you said "airplane" you really meant, jet aircraft or multi-engine aircraft, your example is more solid.  :-)

 

Russell

[smdion]

BJP,

 

Just an FYI - most single engine aircraft (non-jet) can't exceed much over 200 MPH.

 

If, when you said "airplane" you really meant, jet aircraft or multi-engine aircraft, your example is more solid.  :-)

 

Russell

 

The things I learn on the unRAID forums

[garycase]

Too bad Jim Bede's infamous BD-10 never made it to market 

I had a friend (retired military pilot) who was planning to build one ~ 20 years ago.

 

THAT would not have had any problem with Brian's speed limits  8)

[SSD]

Everyone's a critic!