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

[John Kozubik]

On Tue, 13 Feb 2007, Eric Anderson wrote:

> > 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.
>
> Uhh, aren't those threads below at *least* a year old, or am I
> misreading it?  If so - then I think you in fact need to become more
> informed, since massive UFS updates have been done in the past 6 months.
>   If you have pointers to more recent issues, please post them..


[1] Is from January 2006, and is currently acknowledged as an existing
problem that _is not_ fixed in 6.2.  Apparently there is some pretty
heavy lifting that needs to be done to fix this "fill disk while
snapshotting"  problem.  It is an open, current problem.

[2], as I state below, has been fixed, but I keep re-demonstrating it
every other release or so.  It has been my observation that high volume
inode movement on snapshotted UFS2 filesystems keeps popping up as a
problem.


I think you misunderstand my point in all of this.  None of it affects me
at all - I keep abreast of freebsd-fs, I test things, and I, like many
others, simply don't use these features.  The end.

My point is not to complain about the current state of snapshots and
bg_fsck.

My point is that the average user is not active on these lists and should
not be subject to an _enabled by default_ feature set that is dangerous.
If they want to use snapshots and bg_fsck, then by all means - but have
them turn it on themselves with some warning as to the ramifications of
doing so.


> > [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...


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