USB I/O very slow

[UnixRocks]

So write-caching is not an advantage or something possible in FreeBSD.

That is not what I said. A write cache merely caches the data in RAM. It does not speed up media writes. The speed of writes is due to a combination of hardware + driver in almost all cases. (I can't think of times where that is not the case, but I say "almost" since there may be other factors that have slipped my mind or of which I am unaware. )

 

[Crivens]

FreeBSD uses a timer for having flushing the data to disk. It is per default set to 30 seconds, so you may see 30 seconds of high speed writing followed by the slow down as the vnode gets drained to the storage. The tuning guide should have more information about this. You may get the "true" timigs for Linux when you copy the file and follow the cp with a sync command.

 

[Isaac Monteiro]

Thank.
I will try mount the stick with sync() in Linux.

After some tests, I noticed that the "system" slow down is on chromium only.

But anyway, Thanks.