MySQL performance problems
These sites ran well for a week or so and then MySQL would start to drag, and the load average would go up. My pages that would normally take 0-2 seconds to generate were now taking 30 or more seconds. At first I thought that this was due to increased hits and not enough memory but in fact the hit rate stayed fairly constant. I often found that just restarting MySQL and Apache would settle things down.
So to "fix" this I upgraded to a Linode 128 and then to a Linode 256. I'm still having the problem and it's worse now. Things were very smoother for about 10 days after moving to the Linode 256 and then early Friday morning MySQL became very slow again and hasn't let up. Unlike pervious times, where restarting MySQL or just waiting a few hours would fix things, nothing is helping and my MySQL based websites are unusable.
Anyone have any insights on what may be causing this? Does anyone else have any similar problems?
Thanks,
Geoff
2 Replies
vmstat 1 (a few lines, look for swapping)
and
ssh [linodeusername]@host[yourhost#].linode.com io_status
-Chris
io_status shows:
OK iocount=850802 iorate=27 iotokens=200000 tokenrefill=512 token_max=200000
vmstat 1 shows:
procs memory swap io system cpu
r b w swpd free buff cache si so bi bo in cs us sy id
0 0 0 1068 12864 12044 135524 0 0 19 17 138 44 24 41 35
1 0 0 1068 12728 12052 135652 0 0 132 0 242 101 26 35 38
1 0 0 1068 12728 12052 135652 0 0 0 0 106 11 42 58 0
1 0 0 1068 12728 12052 135652 0 0 0 0 105 11 35 65 0
1 0 0 1068 12728 12052 135652 0 0 0 0 105 13 32 68 0
1 0 0 1068 12724 12056 135652 0 0 0 91 195 14 33 67 0
1 0 0 1068 12724 12056 135652 0 0 0 0 106 11 42 58 0
0 0 0 1068 12712 12056 135664 0 0 0 0 107 25 2 6 92
1 0 0 1068 12640 12056 135664 0 0 0 0 108 19 0 5 95
0 0 0 1068 12452 12060 135664 0 0 0 89 198 38 0 0 100
0 0 0 1068 12612 12064 135748 0 0 85 46 240 82 3 5 92
1 0 0 1068 12544 12064 135824 0 0 60 0 177 157 11 30 60
1 0 0 1068 12544 12064 135824 0 0 0 0 105 13 29 71 0
1 0 0 1068 12544 12064 135824 0 0 0 0 103 12 25 75 0
1 0 0 1068 12544 12064 135824 0 0 0 0 103 11 51 49 0
1 0 0 1068 12540 12068 135824 0 0 0 130 234 16 40 60 0
1 0 0 1068 12540 12068 135824 0 0 0 0 104 10 41 59 0
0 0 0 1068 12540 12068 135824 0 0 0 0 107 25 18 20 62
0 0 0 1068 12540 12068 135824 0 0 0 0 102 15 0 0 100
0 0 0 1068 12540 12068 135824 0 0 0 0 102 9 0 0 100
0 0 0 1068 12540 12068 135824 0 0 0 26 128 20 0 0 100
0 0 0 1068 12540 12068 135824 0 0 0 0 102 9 0 0 100
0 0 0 1068 12540 12068 135824 0 0 0 0 102 11 0 0 100
Also, CPU is running at close to 100% with 60%-75% in the system.