Hi here,
Our server had 2GB of RAM. We added some memory to have 16GB. We are on a debian etch. I installed the "bigmem" kernel to use the all memory :
~# cat /proc/meminfo
MemTotal: 16573232 kB
MemFree: 15448836 kB
Buffers: 133772 kB
Cached: 445388 kB
SwapCached: 0 kB
Active: 782764 kB
Inactive: 302760 kB
HighTotal: 15794120 kB
HighFree: 14838384 kB
LowTotal: 779112 kB
LowFree: 610452 kB
SwapTotal: 2658716 kB
SwapFree: 2658716 kB
Dirty: 452 kB
Writeback: 4 kB
AnonPages: 506336 kB
Mapped: 126524 kB
Slab: 27620 kB
PageTables: 3036 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
CommitLimit: 10945332 kB
Committed_AS: 2187952 kB
VmallocTotal: 118776 kB
VmallocUsed: 3716 kB
VmallocChunk: 114640 kB
I wanted to give to postgres 4GB. So I tryied to set shmmax to 4Go :
sysctl kernel.shmmax=4294967296
But it doesn't work : if I launch after this modification this command :
sysctl kernel.shmmax
it gives me this response :
kernel.shmmax = 0
Why? Is there a limit to shmmax?