This IS the Avid L2: Re: [Avid-L2] G-Raid transfer speeds

Friday, May 9, 2014

Re: [Avid-L2] G-Raid transfer speeds - USB3 vs Thunderbolt

Data density increases with larger capacity drives. Thus, the same rotational speed is able to read and write at higher rate.

160MB/s is likely empty or near empty. At 80% full and moderate fragmentation, you will likely see up to 50% drop in overall transfer rate.

On 5/9/2014 8:39 PM, Michael Brockington brocking@sfu.ca [Avid-L2] wrote:

Makes sense, Dom, thanks. I wasn't aware the higher capacity drives were faster as well.

Would you expect 160 MB/s to be the average across the drive as it fills up, or what you would get with an empty drive?

Thanks,
--Michael

On 14-05-09 5:32 PM, 'Dom Q. Silverio' domqsilverio@gmail.com [Avid-L2] wrote:

SATA via TB is more efficient than SATA to USB conversion. It is not
surprising TB would achieve higher speeds.

These kind of benchmarks are usually done when the drives are empty.
Spindle based drives slowly decrease in transfer rate as the drive fill
with data and fragments. With 4TB drives 160 MB/s is not surprising. I
was able to achieve ~130 MB/s with an empty 2TB drive.

On 5/9/2014 8:11 PM, Michael Brockington brocking@sfu.ca [Avid-L2] wrote:
> I'm trying to understand why the transfer rates G-Drive claims for it's
> G-Raid are quite different between the USB-3 and Thunderbolt versions.
> On their website they claim the USB3 G-Raid does 250 MB/s, and the
> Thunderbolt version does 327 MB/s - 30% faster.
>
> But it seems to me the limiting factor in both cases would be the speed
> of the underlying hard drives. I think both products use a pair of 7200
> rpm drives raided together. I've always thought a single 7200 drive was
> good for about 120 MB/s sustained, so a pair would get you around 240
> MB/s. That seems to match the spec for the USB-3 G-Raid pretty well,
> but not the Thunderbolt version.
>
> Since both USB-3 and Thunderbolt interfaces are significantly faster
> than the throughput of a pair of raided disks, why the difference?
>
> Anyone have any real-world experience with the 2 variations, is there
> really that much difference in speed?
>
> At 327 MB/s, they seem to be getting about 160 MB/s per disk (which is
> about the same transfer rate they claim for a single G-Drive) -- does
> that match people's experience? I notice that LaCie, for comparison,
> only claims an average transfer rate of 110 MB/s for their 7200 rpm
> rugged drives, which seems more in line with the numbers I'm used to seeing.
>
> Links to specs:
> http://www.g-technology.com/products/g-raid
> http://www.g-technology.com/products/g-raid-thunderbolt
> http://www.g-technology.com/products/g-drive-thunderbolt
> http://www.lacie.com/us/products/product.htm?id=10599
>
> Thanks,
> --Michael
>
>
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