more then 2G shm on RELENG_7

Benjamin Sobotta mayday at
Wed Dec 5 05:53:47 PST 2007

> Hello,
> I'm to test PostgreSQL on a 7-BETA3. The box has 12GB of memory in it,
> I've adjusted the sysctls, but postgresql always fails to allocate the
> SHM if it's bigger then 2GB.
> How can I make it to allocate more SHM than 2G at once?
> sysctl.conf:
> kern.ipc.shmall=1572864
> kern.ipc.shmmax=6442450944
> kern.ipc.semmap=1024
> kern.ipc.shm_use_phys=1
> /boot/loader.conf:
> zfs_load="YES"
> vm.kmem_size="1073741824"
> vm.kmem_size_max="1073741824"
> kern.ipc.semmni=1024
> kern.ipc.semmns=2048
> kern.ipc.semmnu=1024
> I've also hit a similar issue with qemu, but that wasn't shared memory,
> I had just tried to make it allocate more than 2GBs for a single vm, but
> that also failed. Still haven't figured out why was that.
> Sincerely,
> Gergely Czuczy
> mailto: gergely.czuczy at
> -- 
> Weenies test. Geniuses solve problems that arise.


I'm not sure if this is helpful, as I dont run FBSD 7 as of yet. Further I'm not very familiar with the topic. But I had a similiar problem with MySQL on 6.2. What helped for me was play with 


in loader.conf. 



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