restore(8) to UFS on USB key: terrible slow

Matthias Apitz guru at
Fri Dec 9 06:21:27 UTC 2011

El día Thursday, December 08, 2011 a las 09:57:13AM -0600, Dan Nelson escribió:

> Cheap USB thumb drives aren't really optimized for small random-I/O writes. 
> Can you try mounting the filesystem async?  that might help a little.  A
> workaround would be to use mdconfig to create a block device (backed by
> either swap or a file on your hard drive) the same size as your flash drive,
> newfs and restore to that, then umount the filesystem and dd the raw image
> directly to your flash drive.

Hello Dan,

Thanks for your hints. I tend to add that those USB thum drives aren't
good for anything. I have a certain number of them containing each a
complete bootable FreeBSD (including 'src', 'obj' and binary packages)
to install my laptops and netbooks from them;

after some time these USB keys tend to loose data:
files are corrupt a bit, dirs are missing and so on; that's
why I wanted to make dump(8) nackups of them, to restore them from time
to time; I will drop the idea and will just make dd(1) backups of the
full /dev/da0;


Matthias Apitz
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e <guru at> - w
UNIX since V7 on PDP-11 | UNIX on mainframe since ESER 1055 (IBM /370)
UNIX on x86 since SVR4.2 UnixWare 2.1.2 | FreeBSD since 2.2.5

More information about the freebsd-questions mailing list