Re: [Discuss-gnuradio] Hard Disk Bottleneck

[Ryan Seal]

Vincenzo Pellegrini wrote:
> Hi everybody,
>
> just a quick question: has anybody managed so far to provide the usrp
> with the 8 Complex Msps needed to transmit an 8 MHz wide band?
>
> My problem is that such a bandwidth yields a 32MiBps throughput and,
> even if the USB2 bus and the CPU speed of my machine are all right with
> this, it looks like my IDE HARD DISK cannot provide such a data rate.
>
> Can anyone please confirm whether he's been successful in something
> similar, and, if so, with what kind of HD?
>
> thanks
>
> vincenzo 
>
>
>
>
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>   

You can successfully store data at those rates using SATA-II drives. You 
can also set up a RAID-O configuration with IDE drives and should get 
enough bandwidth. Actually we are using a more intensive system here 
with 8 SATA-II drives using an areca PCI-E card with a RAID-5 
configuration and achieve continuous rates close to 200MBPS - so I know 
it can be done.

If you format your IDE drive and use a benchmarking program, you will 
typically see that, as the disk fills, data write speeds decrease 
linearly due to your position on the disk. You can sometimes look at the 
numbers and then create a smaller partition that can maintain these speeds.

Also, using isolated drives for data is important and we find the XFS 
filesystem to outperform all other filesystems for continuous writing.

Ryan