>>> Swap usage on Linux always seems a little tricky to me. Should my >>> goal on a web server be zero swap usage, meaning the attached graph >>> should show no green lines at all if I'm doing it right? >>> >> >> No. You want things that aren't in use to be swapped, like memory >> leaks and such. You don't want things that will be used to be >> swapped. > > > Does this look OK? It looks to me like heavy swapping in and out with > plenty of free memory (minus buffers/cache).
Or put another way, how do I know when swapping is a problem? I'm running munin so I can look over graphs of my system's characteristics but I'm not sure what to look for to determine if I'm swapping excessively. - Grant > # vmstat 1 20 > procs -----------memory---------- ---swap-- -----io---- -system-- > ------cpu----- > r b swpd free buff cache si so bi bo in cs us sy id wa > st > 0 1 155308 71328 29200 2437260 1 0 127 63 0 0 48 > 1 50 1 0 > 0 1 155308 44444 29204 2465164 0 0 27772 0 1483 1236 1 > 1 74 24 0 > 2 2 155480 32904 29220 2476392 0 172 33684 172 4166 2790 44 > 2 30 24 0 > 4 0 155828 30332 29220 2479756 0 348 41388 348 5319 1884 76 > 2 1 21 0 > 1 1 156184 37668 29244 2470752 0 356 28960 424 5033 3299 53 > 2 15 29 0 > 0 2 156412 32912 29264 2477364 0 228 30976 252 2909 2516 14 > 2 56 29 0 > 2 5 156640 29372 29400 2480328 0 228 23180 344 3949 3156 32 > 2 35 31 0 > 1 4 157072 36372 29624 2469924 0 432 28032 488 4120 3289 50 > 2 10 37 0 > 2 4 157260 37372 29812 2466036 0 188 12188 316 3789 2540 54 > 1 7 38 0 > 2 3 157260 30236 29912 2467672 0 0 16372 48 3730 2077 57 > 2 8 34 0 > 2 3 157304 29684 28940 2459688 24 44 10892 44 4271 2808 44 > 2 11 43 0 > 5 2 157824 36448 28372 2440176 4 520 13036 620 4796 3185 56 > 2 10 33 0 > 2 3 157928 34552 28516 2437032 4 104 19620 148 4446 4108 48 > 3 15 35 0 > 2 6 157928 38620 28444 2385828 436 0 4808 136 4615 2851 39 > 5 6 51 0 > 3 5 157928 36936 28604 2377112 732 0 8072 84 4773 2970 64 > 2 0 34 0 > 5 7 157928 39068 28832 2375944 40 0 2040 492 4877 3341 71 > 2 1 26 0 > 3 4 157928 81820 28984 2376868 188 0 19320 0 5122 6990 66 > 5 0 30 0 > > # free -h > total used free shared buffers cached > Mem: 3.9G 3.8G 41M 88M 20M 2.4G > -/+ buffers/cache: 1.4G 2.4G > Swap: 1.0G 154M 869M
