comments on newfs raw disk ? Safe ? (7 terabyte array)

[John Kozubik]

On Tue, 13 Feb 2007, Oliver Fromme wrote:

>  > > A bit careful here ...  Background fsck had some issues,
>  > > especially when the machine crashed or is otherwise reset
>  > > while the background fsck is still running.  It resulted
>  > > in corruption that could not be repaired by fsck anymore.
>  > > I don't know if all of those issues have been resolved in
>  > > RELENG_6, but personally I always disable background fsck
>  > > on all of my machines, just to be safe.
>  >
>  > [...]
>  > UFS2 snapshots are dangerous and unstable,
>  > and have been since their introduction in 5.x [2].
>
> That's not what I wrote.  I wrote that they _had_ issues,
> and that I do not know if they have been fixed.  I don't
> recall any reports of problems recently (i.e. in the past
> few months), and there are no open PRs that seem to relate
> to the current code, so those issues may very well have
> been fixed.  It's just my personal paranoia that lets me
> disable bg fsck on my machines (and I don't really need
> bg fsck anyway).


Fair enough.  For your information, they are still dangerous and
unstable[1][2][3].  Your initial assessment is still valid today,
unfortunately.  FWIW, [1] is open and relates to the current code.

It (bg_fsck and UFS2 snapshots) has gotten better over time - but it is
still not something that I feel is fair to enable by default, as if it
were rock solid, and force it onto unsuspecting end users who are not as
well informed as you and I are.


John Kozubik - john at kozubik.com - http://www.kozubik.com


[1] http://lists.freebsd.org/pipermail/freebsd-bugs/2006-January/016703.html
[2] http://lists.freebsd.org/pipermail/freebsd-bugs/2004-July/007574.html
[3] [2, above] has been fixed, but large quantity inode movements keep
    coming back to haunt snapshots every other release or so...