Dump time issues

[Chris H]

On Tue, 28 Oct 2014 12:20:01 -0700 Adrian Chadd <adrian at freebsd.org> wrote

> On 27 October 2014 11:09, Kevin Oberman <rkoberman at gmail.com> wrote:
> 
> >> I'm aware of two issues with SU+J, one of which is annoying and the other
> > is worse.
> > 1. If the journal is not fully written on power fail or some other reason,
> > you may need to do a full fsck of the volume and the behavior of the system
> > until this is done can be very unpredictable.
> > 2. You can't safely snapshot the system. This is what 'dump -L' does. This
> > means that some files dumped from a live FS may not be consistent (not
> > good!) or, if '-L' is used, the system may well hang.
> >
> > While I love the fast fsck times (2 or 3 seconds) after a crash, I also
> > question the default. Still, it may be a preferred choice be used for very
> > large file systems where a full fsck would take a very long time as long as
> > the risks are understood. For these systems, ZFS might be a better choice.
> > These arguments do NOT favor it being the default, IMHO.
> 
> If people can reproduce SU+J problems then please file bugs. There
> have been some fixes with the journal handling over the last year or
> so and I haven't had this problem on -HEAD any longer, but it doesn't
> mean it's there.
Problem existed on RELENG_9 as of 1 mos, and 1 wk. ago. I don't
have any useful output to provide (I simply blew away the system
&& re-installed w/o SU+J).

--Chris
> 
> 
> 
> 
> -adrian