started playing with jails

Jonathan Horne freebsd at
Wed Mar 21 20:58:46 UTC 2007

> Bill Moran wrote:
>> In response to Greg Barniskis <nalists at>:
>>> Bill Moran wrote:
>>>> I've had trouble getting programs that use shared memory (such as Postgres)
>>>> to run inside a jail, but it's been a while since I've tried.
>>> Postgres needs this in the host rc.conf:
>>> jail_sysvipc_allow="YES"
>> My experiments with Postgres in jail predate the existence of that setting.
>> When I was working with it, you had to frob a sysctl via /etc/sysctl.conf
>> But even then, I couldn't seem to get it to work -- the Postgres in the
>> jail would corrupt the shared memory of the postgres outside the jail.
>> It was ugly.  Imagine big, wet tears rolling down my cheeks.
>> I haven't had the need to try it in a while, so it might work OK now, I
>> just don't know.
> Ah, now that you mention it I do recall discussions of multiple
> instances peeing in each others pools so to speak. I also thought
> there was discussion of how to fix it, but have no idea where that
> went if anywhere...
> A single instance inside a jail does work quite happily if the knob
> above is set.
> --
> Greg Barniskis, Computer Systems Integrator
> South Central Library System (SCLS)
> Library Interchange Network (LINK)
> <gregb at>, (608) 266-6348

what is the best method for backup?  just back up the whole thing as if it were
"files" on my host?


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