[Ubuntu-be] CopyKitten Benchmarks

[Wouter Vandenneucker]

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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