we have problem with high iowait. it's have been for a week. my cpanel going unstable when office start at morning. smtp/courier-authlib/pop3 notify down, email authentication going wrong. I suspect this is because exim and courier. is there something happened with exim or courier ?
sar -q
08:00:01 AM 1 393 0.46 0.38 0.26
08:10:01 AM 1 398 0.35 0.36 0.29
08:20:01 AM 1 390 0.15 0.25 0.26
08:30:01 AM 6 401 0.36 0.41 0.34
08:40:01 AM 1 397 0.50 0.47 0.38
08:50:01 AM 1 396 1.04 0.84 0.61
09:00:01 AM 2 451 0.84 0.81 0.69
09:11:45 AM 15 538 93.41 38.04 14.53 Office Hour
09:20:01 AM 1 455 1.17 7.84 8.80
09:30:01 AM 1 449 1.31 1.97 5.08
09:40:27 AM 4 622 118.30 60.92 26.22 Office Hour
09:50:01 AM 0 457 1.41 10.44 14.97
10:00:01 AM 2 453 1.20 2.25 8.28
# free
total used free shared buffers cached
Mem: 8265248 8156296 108952 0 526916 6767360
-/+ buffers/cache: 862020 7403228
Swap: 16394292 116 16394176
sar -q
08:00:01 AM 1 393 0.46 0.38 0.26
08:10:01 AM 1 398 0.35 0.36 0.29
08:20:01 AM 1 390 0.15 0.25 0.26
08:30:01 AM 6 401 0.36 0.41 0.34
08:40:01 AM 1 397 0.50 0.47 0.38
08:50:01 AM 1 396 1.04 0.84 0.61
09:00:01 AM 2 451 0.84 0.81 0.69
09:11:45 AM 15 538 93.41 38.04 14.53 Office Hour
09:20:01 AM 1 455 1.17 7.84 8.80
09:30:01 AM 1 449 1.31 1.97 5.08
09:40:27 AM 4 622 118.30 60.92 26.22 Office Hour
09:50:01 AM 0 457 1.41 10.44 14.97
10:00:01 AM 2 453 1.20 2.25 8.28
# free
total used free shared buffers cached
Mem: 8265248 8156296 108952 0 526916 6767360
-/+ buffers/cache: 862020 7403228
Swap: 16394292 116 16394176