Will two 6gbps HDDs running RAID 0 be capable of 12gbps?

bazintexas

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Sep 15, 2013
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Not going with SSD at this time, but curious if I could get twice the throughput runnung two 6gbps HDDs with RAID 0.

Thanks!
 
Solution
Sorry, as ssimpss stated, it doesn’t work that way.

HHDs can be SATA 6Gb/s "compatible", but are not 6Gb/s "capable".
SATA 3 (6Gb/s) speeds are from 301MB/s to 600MB/s. No HDD can spin fast enough to achieve SATA 3 speeds.

SATA 3 HDDs have a buffer in them (16MB, or 32MB, or 64MB) which can transfer their contents at 6Gb/s speeds, but that’s all.

One of the fastest SATA 3 HDDs on the market is the Seagate Barracuda and it has average Read/Write speeds of 156MB/s and maximum burst speed of 210MB/s.
FYI, SATA 2 (3Gb/s) speeds are from 151MB/s to 300MB/s.

So, if you had 2 Barracuda’s in RAID-0, your average Read/Write speeds would be barely over 300MB/s.
Sorry, as ssimpss stated, it doesn’t work that way.

HHDs can be SATA 6Gb/s "compatible", but are not 6Gb/s "capable".
SATA 3 (6Gb/s) speeds are from 301MB/s to 600MB/s. No HDD can spin fast enough to achieve SATA 3 speeds.

SATA 3 HDDs have a buffer in them (16MB, or 32MB, or 64MB) which can transfer their contents at 6Gb/s speeds, but that’s all.

One of the fastest SATA 3 HDDs on the market is the Seagate Barracuda and it has average Read/Write speeds of 156MB/s and maximum burst speed of 210MB/s.
FYI, SATA 2 (3Gb/s) speeds are from 151MB/s to 300MB/s.

So, if you had 2 Barracuda’s in RAID-0, your average Read/Write speeds would be barely over 300MB/s.
 
Solution
With a proper card, I am sure you can get higher speeds, but you will need many drives.

Also mote that while RAID0 helps sequential read/write operations. It does NOT help access times at all.

Access times are one of the things that make SSDs so damn fast. I mean I have had raid0 volumes faster than single ssds(sequential), but the single ssd is always faster in day to day use.
 

ssimpss

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Sep 3, 2013
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Your forgetting the vlociraptors very quick HDD and now in 1Tb version
 
No, the VelociRaptors would give you slightly better performance in RAID-0 than the Barracudas in RAID-0. You probably won't notice the difference between the two in real-world performance.
I was just trying to make the point that HDDs advertised as SATA 3 is mostly for Marketing purposes.
 

ssimpss

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Sep 3, 2013
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Right got you, I know how to set up raid 1,0 whatever I try and dodge software and benchmarks as much as I can though. But I don't want to give out bad or worse wrong information on forums or even worse to paying customers. Thanks for the help
 
The raptors better access times(due to the faster rotational speed) will more than make up for a slight speed loss over the new 1tb per platter seagate drives in day to day use.

Another option is to short stroke a larger drive. The shorter the distance the head has to move, the better the access times are. It also keeps the data in the fastest part of the drive.

Remember for storage you may not need so much speed. OS drives on the other hand need as much as you can get :)
 
NO.
6gb refers to the hard drive buffer to sata rate. Unfortunately, the hard drive platter to buffer rate maxes at perhaps 200mb/s.

And, the raid-0 speed only happens during sequential operations using synthetic benchmarks that allow overlap of two drives. Most apps do not have that capability.

If you want performance, look at a SSD.