> > 
> > And it seems quite slow, even with mounting async...
> 
> What you're almost certainly seeing is the "pseudosynchronous I/O"
> effect cause by either running out of vnodes or running out of metadata
> buffers.  The first is easy to fix; use sysctl to bump kern.maxvnodes,
> a *lot*.
> 
> The latter is harder, but unless you have a truly huge number of files
> and directories delete, you should not see it.

That's an interesting suggestion. I'll try it next time when I'll do
large copying.

Thanks	Pavel