Current status of nullfs and/or unionfs?

EirikØverby ltning at
Fri May 6 03:44:29 PDT 2005

On 05-05-05 16:59, "Marc G. Fournier" <scrappy at> wrote:

> On Thu, 5 May 2005, Eirik [ISO-8859-1] Øverby wrote:
>> The solution, or at least parts of it, would be to have certain parts of
>> the jail filesystems mounted in via nullfs (acceptable solution) or
>> unionfs (ideal solution). However, ever since FreeBSD 4.10 this has been
>> a major problem, as both filesystems started exhibiting major stability
>> and data integrity issues.
> I'm running 4.11 with ~90 mount/jails running on two of our servers ...
> haven't noticed any stability problems ... what are you seeing?

I was seeing panics and deadlocks (hangs), seemingly unrelated to the level
of disk activity, and sometimes I even had the suspicion that just having
such a mountpoint, even though the jail wasn't started, could be enough to
bring the system down. The problems appeared around 4.9/4.10.
Even though I mounted these read-only, I still saw data going bad in
directories that was null-mounted. This scared me away for a very long time

I'm just now picking up on the unionfs use, seems to do what I want, but I
have no idea if it's stable or not. I suppose we'll be seeing that soon.


> ----
> Marc G. Fournier           Hub.Org Networking Services (
> Email: scrappy at           Yahoo!: yscrappy              ICQ: 7615664
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