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?