[Ubuntu-be] CopyKitten Benchmarks

[Claudio Mammarella]

Hey wouter ,

When i use DD i'm copying from a disk or an image file of the same size 
as the target drive.
So the drive or image has to be the exact same size, then there is no 
"unallocated memory"

I don't think that we can write 4gb under 3 minutes with our usb-drives 
(class4)
Class 4 means min. 4MB/s and it will take about 15 to 20 minutes to 
write a single usb-drive (4gb).
You wrote from 2,5 to 5 minutes for 700mb, (4000MB:700MB)x4min=22 min/drive

grts
Claudio

Op 28-09-12 13:31, Wouter Vandenneucker schreef:
> Hi all
>
> So I'm messing around a bit with CopyKitten. Turns out: there are some 
> glitches in the code..
> For some reason today the usb drives where written 1 by 1. I'll be 
> fixing that later today on the train.
>
> *Benchmarking*
> *
> *
> This did allow me to do some benchmarking automated (I could get 3 
> sticks to write and log the time without having to sit behind my 
> computer).
> Writing an ISO from one USB drive to the others takes an aweful amount 
> of time because it goes through the total 4GBs of memory even when 
> only 700MB is written.
> Using an ISO file goes a lot faster.
>
> *Unallocated memory*
> *
> *
> When I tried to use the normal Ubuntu 12.04 ISO it resulted in a 
> bootable 700MB partition and 3.3GB of unallocated memory.
> I'm going to experiment with 2 partitions on the USB drive, because I 
> believe that allocating that memory is faster than writing "empty 
> space" to the drive using ddrescue.
>
> I let the program write 3 USB drives the times needed to do that are 
> roughly: 5 minutes, 2.5 minutes, 3 minutes. Way less than writing from 
> USB to USB.
> However, you should note that those times are for 700MB ubuntu 
> bootable and 3.3GB unallocated.
>
> Claudio, how do you solve this "unallocated memory"?
>
> *Blocksize*
> *
> *
> One of the other "optimizations" I made is changing the default 
> block-size at which ddrescue writes to the usb drives. It turns out 
> that 5MB goes well, and depending on the harddrive you could crank 
> that up. I'll be testing some drives here but I am wondering how fast 
> we could get using an SSD with optimized blocksize.
>
> (if we can write 4GB in less than 3 minutes we don't need to worry 
> about allocating memory)
>
> *Future steps*
> *
> *
>
>   * For now I'm going to change to code to write all drives at once
>   * Optimze the blocksize even further
>   * Get rid of a bug that you encounter when you use an ISO instead of
>     a master drive
>
>
> Grts
>
>
> Wouter
>
>

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