small update: I fixed the 1-drive-at-once-bug. Turned out I misplaced my "&".
Anyhow, we're now successfully writing 700MB to 3 drives in under 2 minutes.. Grts Wouter 2012/9/28 Wouter Vandenneucker <[email protected]> > 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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