Hi Rik,
We are having a sever VM problem while running
Tomcat (Java proc) on a stock RedHat 7.2, with
a 2.4.7-13enterprise kernel.
What happens is that after a while the box stops
responding, without oopsing. It can still be pinged,
but not more than that. VT switching still works,
alas slowly. You can still type a login name, but
chars are echoed to the screen with a .5-1s delay.
After you press <ENTER>, nothing happens.
It looks like the system spends 100% of it's time
in the kernel, doing some VM-related thing.
Here are the details for the box:
-- RAM: 768MB
-- Swap: 512MB
-- Java: maximum heap of 512MB
We've capture the vmstat of one of this cases.
In this particular case the OOM killer managed to
finally kill the offending java process, and the
system recovered:
Jan 9 21:20:00 vangogh CROND[6256]: (root) CMD (/usr/lib/sa/sa1 1 1)
Jan 9 21:20:23 vangogh timed[1111]: measure: renoir did not respond
Jan 9 21:24:20 vangogh timed[1111]: measure: renoir did not respond
Jan 9 21:27:28 vangogh kernel: Out of Memory: Killed process 6276 (java).
Jan 9 21:28:18 vangogh kernel: Out of Memory: Killed process 6300 (java).
Jan 9 21:28:25 vangogh kernel: Out of Memory: Killed process 6301 (java).
Jan 9 21:28:31 vangogh kernel: Out of Memory: Killed process 6302 (java).
Jan 9 21:28:27 vangogh timed[1111]: measure: renoir did not respond
Jan 9 21:28:43 vangogh kernel: Out of Memory: Killed process 6303 (java).
Jan 9 21:29:30 vangogh kernel: Out of Memory: Killed process 6304 (java).
Jan 9 21:29:55 vangogh kernel: Out of Memory: Killed process 6305 (java).
Jan 9 21:29:59 vangogh kernel: Out of Memory: Killed process 6306 (java).
Jan 9 21:29:59 vangogh kernel: Out of Memory: Killed process 6307 (java).
Jan 9 21:30:00 vangogh CROND[6571]: (root) CMD (/usr/lib/sa/sa1 1 1)
Here's the #vmstat 2 output:
[cellbucksdev@vangogh cellbucksdev]$ vmstat 2
procs memory swap io system
cpu
r b w swpd free buff cache si so bi bo in cs us sy
id
4 0 0 0 51836 71572 170748 0 0 6 21 112 174 3 0
97
3 0 0 0 46868 71572 170764 0 0 0 0 198 605 33 3
64
3 0 0 12576 3336 65416 159800 0 0 0 98 254 693 83 17
0
6 0 0 12576 3512 51752 126056 0 0 10 0 194 1802 85 15
0
2 0 0 12576 3056 44560 104992 0 0 0 76 118 2653 92 8
0
3 0 0 12576 9368 39844 44216 0 1946 8 2024 162 2526 81 19
0
3 0 0 59976 4120 28016 38944 0 2618 2 2632 152 2497 88 12
0
3 0 0 115864 2708 8416 30768 0 0 216 42 148 2224 88 10
2
4 2 1 248504 1760 440 28792 156 7032 522 7054 218 1365 56 11
33
3 0 1 267764 2548 496 28448 310 10060 332 10092 343 1556 16
9 75
2 0 1 296652 1952 496 27352 198 13674 204 13698 293 4586 57
8 35
2 2 0 302764 2512 552 27468 162 14422 286 14424 293 1105 14
6 79
4 0 2 318472 2544 584 27424 104 12164 154 12196 311 2506 40
15 45
6 1 0 342588 2136 584 26772 182 13660 214 13662 321 2767 39
15 46
1 1 1 326780 2972 600 26660 6884 6618 6884 6692 348 3148 63
9 28
1 1 1 321488 2928 600 26396 6574 8378 6574 8392 351 3573 67
7 26
3 0 0 316504 3012 580 26184 6012 7186 6016 7204 372 3522 73
8 18
3 0 0 287996 3052 596 24228 6490 4234 6490 4308 327 3203 66
10 25
1 2 1 281788 3056 604 25888 2838 4176 3702 4188 301 2480 49
3 48
6 0 0 276332 3004 620 24840 4152 5020 4152 5062 299 2684 68
7 25
2 2 1 272396 3392 556 24960 5602 5884 5668 5918 320 2754 55
6 39
6 0 0 272680 3056 556 23884 3314 4948 3318 4964 359 3224 69
9 22
procs memory swap io system
cpu
r b w swpd free buff cache si so bi bo in cs us sy
id
8 1 0 278040 2556 572 23876 3502 6510 3512 6574 298 2910 54
8 38
5 0 0 287368 1812 588 23700 432 6996 500 7010 297 2433 57 6
36
5 0 0 299720 3024 596 20188 212 6328 212 6370 210 2332 60 6
34
3 1 0 321520 2552 600 16920 146 9274 232 9312 285 1735 35 8
57
7 0 1 357440 2592 584 12600 206 5920 206 5922 256 2550 58 6
35
0 2 1 414292 1920 584 12356 210 4758 210 4852 269 1826 42 16
42
3 0 0 412600 1868 584 12364 488 7900 488 7900 280 984 29 4
67
2 0 4 419532 2048 596 11500 548 5690 548 5738 262 2542 61 8
31
0 2 1 418720 2860 592 11168 434 5178 434 5204 217 1169 30 3
67
5 1 1 417344 2744 612 9564 666 6160 748 6172 307 1716 39 8
53
2 0 0 440744 2040 628 9492 374 8888 386 8916 247 1511 45 8
47
4 0 0 471220 2548 628 8916 392 6844 414 6850 237 2269 49 9
42
1 2 1 474212 2292 612 8684 3364 8092 3390 8114 344 2944 51
8 40
0 2 1 484720 2048 612 8132 2348 6076 2356 6144 316 1174 16
4 80
7 0 1 530088 2824 524 6420 568 13354 598 13366 510 1007 6
9 85
1 1 1 530100 1804 548 6352 426 7682 686 7754 268 1622 24 27
50
0 2 1 523096 2356 564 6952 662 8984 1030 8984 297 586 2 15
82
1 2 3 514984 2616 580 6844 246 8388 246 8402 414 417 3 11
86
2 1 0 505276 2336 580 6896 266 11302 296 11304 326 661 0
5 95
5 2 1 528160 3056 552 6728 490 9606 490 9606 355 928 4 9
87
2 2 1 530060 1528 548 6220 1882 5602 1884 5602 383 832 3
3 93
7 0 1 530096 2048 528 6048 178 10928 178 10928 379 561 0
10 90
procs memory swap io system
cpu
r b w swpd free buff cache si so bi bo in cs us sy
id
9 0 0 530104 2556 516 5684 206 7676 206 7676 310 377 1 30
69
7 0 0 529960 2548 500 4660 298 8506 298 8512 328 396 2 18
80
4 0 0 530096 2536 476 4084 240 7226 240 7226 360 458 0 18
81
2 4 1 530072 1776 300 784 274 5228 290 5234 367 585 0 39
61
20 2 1 530104 1844 300 564 1806 472 15460 472 1702 7418 0 99
1
6 15 2 530100 1564 308 972 7432 382 88178 518 9773 38300 0 100
0
15 7 1 530104 1824 304 540 3618 66 70724 152 6303 31206 0 100
0
5 3 1 128004 484600 704 7056 1440 0 9964 100 799 3279 0 70
30
1 0 0 127996 480132 940 8580 1426 0 2294 36 255 576 1 1
97
1 0 0 117396 475396 964 11104 4026 0 5300 0 221 560 1 3
96
1 0 0 117380 461336 996 11104 6876 0 6880 80 348 686 9 0
91
1 0 0 117380 446864 996 11168 7028 0 7060 0 1106 873 24 2
74
1 0 0 35064 469940 1016 11432 4394 0 4530 20 716 726 16 3
81
0 0 0 31768 470416 1016 11432 292 0 292 0 114 143 0 0
100
0 0 0 31768 470416 1016 11432 0 0 0 0 103 113 0 0
100
0 0 0 31768 470416 1016 11432 0 0 0 0 103 113 0 0
100
0 0 0 31768 470416 1040 11432 0 0 4 18 108 121 0 0
100
0 0 0 31768 470416 1048 11432 0 0 0 8 105 116 0 0
100
0 0 0 31768 470416 1048 11432 0 0 0 0 104 113 0 0
100
0 0 0 31768 470416 1048 11432 0 0 0 0 107 113 0 0
100
0 0 0 31768 470416 1048 11432 0 0 0 0 103 112 0 0
100
0 0 0 31768 470416 1048 11432 0 0 0 0 104 114 0 0
100
0 0 0 31768 470416 1048 11432 0 0 0 0 104 112 0 0
100
I appologise if the output gets mangled by my mailer (I hope not!).
If so, I can resend it as an attachment.
Any help with this problem would be greatly appreciated as this
particular application is one of our most important projects.
TIA,
Dimi.
> We are having a sever VM problem while running
> Tomcat (Java proc) on a stock RedHat 7.2, with
> a 2.4.7-13enterprise kernel.
Please upgrade to the RH 2.4.9 errata kernel.
On Fri, 11 Jan 2002, Dimitrie Paun wrote:
> It looks like the system spends 100% of it's time
> in the kernel, doing some VM-related thing.
> In this particular case the OOM killer managed to
> finally kill the offending java process, and the
> system recovered:
OK, so kernel 2.4.7-13 has a VM bug when running OOM. There are
two possible approaches to getting rid of this bug:
1) upgrade to a kernel which runs ok when pushed near OOM,
like 2.4.17 with my -rmap patch ... but if you do run
OOM with the newer kernel (a bit harder with 2.4.8 and
newer) your JVM will still be killed
2) add more swap or ram to the machine, so you have space
for the program you're trying to run
> Jan 9 21:29:59 vangogh kernel: Out of Memory: Killed process 6307 (java).
> procs memory swap io system
> cpu
> r b w swpd free buff cache si so bi bo in cs us sy
> id
> 0 2 1 484720 2048 612 8132 2348 6076 2356 6144 316 1174 16
> 4 80
> 7 0 1 530088 2824 524 6420 568 13354 598 13366 510 1007 6
> 9 85
> 1 1 1 530100 1804 548 6352 426 7682 686 7754 268 1622 24 27
> 50
> 0 2 1 523096 2356 564 6952 662 8984 1030 8984 297 586 2 15
> 82
> 1 2 3 514984 2616 580 6844 246 8388 246 8402 414 417 3 11
> 86
As you can see, you're really running OOM here, with very
little memory available for cache or buffers. You probably
want to add more swap space and/or ram in order to get
performance.
regards,
Rik
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