started playing with jails

Antony Mawer fbsd-questions at
Wed Mar 21 21:38:32 UTC 2007

On 22/03/2007 3:50 AM, Greg Barniskis wrote:
> Bill Moran wrote:
>> 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.

 From memory, I think the discussion went something like "Postgres uses 
the TCP port number it binds to as its SYSV IPC ID... so if you want to 
run multiple instances in jails/etc without conflict, run them on 
different port numbers (and consequentially they will get separate SYSV 
IPC IDs)".


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