Current status of nullfs and/or unionfs?

EirikØverby ltning at
Fri May 6 04:20:26 PDT 2005

On 06-05-05 13:14, "Danny Braniss" <danny at> wrote:

>> On 06-05-05 09:25, "Danny Braniss" <danny at> wrote:
>>>> Interesting approach. Is this with 4.x or 5.x? How do you union-mount /etc
>>>> (mount command/fstab entry)?
>>> been doing it since 4.x (i think x < 9)
>> Any idea how unionfs will behave if stacked (more mounts on top of each
>> other)? I was playing with the thought of having a "template" jail directory
>> which I unionmount into my jails, then perhaps use your trick to union-mount
>> a md device into certain points in the jail. Got a gut feeling about that?
> i have the feeling that that will get into trouble :-), but im no expert
> here. If what you mean is:
> mount_unionfs /md-0 /jail-0
> and then 
> mount_unionfs /md-1 /jail-0/xyz
> which is not strickly 'stacked', might work and should be easy to try out, but
> IMHO, breaks the KISS principle :-)

I was more thinking, like,
mount_unionfs -b /jails/jail_template /jails/jail-0
mount_unionfs /md-0 /jails/jail-0/etc
for example.

I could also imagine stacking unionfs on top of nullfs, like
mount_nullfs /cdrom/jail_template /jails/jail-0
mount_unionfs /md-0 /jails/jail-0
mount_unionfs /nfs-0 /jails/jail-0

Sounds weird, I know, but we could use it...

> and also, im not sure if:
> mkdir /jail-0/xyz
> mount_unionfs /md-1 /jail-0/xyz
> is the same as the above.
> danny

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