started playing with jails

Greg Barniskis nalists at
Wed Mar 21 16:51:05 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

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