"Guillaume Smet" <guillaume.smet@xxxxxxxxx> writes: > Here is a top output I had on november 17 when the server completely > hangs (several minutes for each page of the website) and it is typical > of this server behaviour: > 17:08:41 up 19 days, 15:16, 1 user, load average: 4.03, 4.26, 4.36 > 288 processes: 285 sleeping, 3 running, 0 zombie, 0 stopped > CPU states: cpu user nice system irq softirq iowait idle > total 59.0% 0.0% 8.8% 0.2% 0.0% 0.0% 31.9% > cpu00 52.3% 0.0% 13.3% 0.9% 0.0% 0.0% 33.3% > cpu01 65.7% 0.0% 7.6% 0.0% 0.0% 0.0% 26.6% > cpu02 58.0% 0.0% 7.6% 0.0% 0.0% 0.0% 34.2% > cpu03 60.0% 0.0% 6.6% 0.0% 0.0% 0.0% 33.3% > Mem: 3857224k av, 3495880k used, 361344k free, 0k shrd, 92160k buff > 2374048k actv, 463576k in_d, 37708k in_c > Swap: 4281272k av, 25412k used, 4255860k free 2173392k cached > As you can see, load is blocked to 4, no iowait and cpu idle of 30%. Can you try strace'ing some of the backend processes while the system is behaving like this? I suspect what you'll find is a whole lot of delaying select() calls due to high contention for spinlocks ... regards, tom lane
