increasing dd disk to disk transfer rate

[Bakul Shah]

> Bakul Shah wrote:
> >>In the last episode (Jan 12), Christoph Kukulies said:
> 
> >>dd if=/dev/ad2 conv=noerror,sync bs=64k | dd of=/dev/ad3 bs=64k
> > 
> > 
> > So now on the new disk he has files with random blocks of
> > zeroes and *no* error indication of which files are so
> > trashed.  This is asking for trouble.  Silent erros are
> > worse.
> > 
> > He ought to do a file level copy, not disk level copy on
> > unix.  That way he knows *which* files are trashed and can do
> 
> The problem is, FreeBSD panics when it encounters bad sectors in 
> filesystem metadata. I had the same situation ~a month ago and gave up, 
> restoring from old backups. It will also probably panic on corrupted or 
> zeroed metadata, but at least it's on a readable disk...

Good point.  Would fsdb help?  If not someone ought to extend it.