[Novalug] need dd help
novalugml at jgcomp.com
Tue Feb 14 14:18:48 EST 2012
On Tue, Feb 14, 2012 at 09:37:02AM -0500, Paul W. Frields wrote:
> You might want to try a larger logical block size for the dd than 1k.
> This makes a significant difference. Best is to base it on the
> characteristics of the drive, but typically you'll get best results
> around 8k or 16k, without much loss with bigger sizes like 1M. What
> you want to do is avoid fighting the drive's built in write buffering
What drive characteristic? I think the physical sector size is
still 512 bytes, no? The 4k or larger block sizes are file system
characteristics which have little involvement here.
Maybe cylinder size? Or the disk's ram buffer size?
I sometimes wonder about dd's input buffer requirement in tasks
such as this. While the read from /dev/zero is probably very
fast, in this usage it only needs be done once. The buffer
could be reused as it is unchanging.
Jon H. LaBadie novalugml at jgcomp.com
11226 South Shore Rd (703) 787-0688 (H)
Reston, VA 20190 (609) 477-8330 (C)
More information about the Novalug