[solved] Usually showing "cannot display the web page"

[redstrike]

Hello,

I am using LiteSpeed 4.1.4. I usually got the "cannot display the web page" after a few hit to navigate, in front-end, back-end, phpmyadmin too.

I don't know why. But server is running normally, not disk i/o, not high load, in very fast state. Although, it returns error page the database is working and update my queries.

[webizen]

anything in the error log (e.g. /usr/local/lsws/logs/error.log)? what platform (OS version, etc) in question?

[redstrike]

anything in the error log (e.g. /usr/local/lsws/logs/error.log)? what platform (OS version, etc) in question?
Nothing special in error.log, I am using CentOS 5.6

It's seem that problems happen in peak hours. My VPS remains a lot of RAM, CPU not high load, no disk I/O.

[redstrike]

I have found that top shows %CPU of litespeed instane is > 99% for a coupe of seconds.

What is the problem in this case?

[sysmesh]

I can add that on my machine all wordpress sites give 403 errors whenever you edit a post and add ANY html valid element in them (i.e. <br> or <b></b>). It will error out on 403 upon save.

I had to roll back to 4.1.3 to solve it.
There seems to be some bug in 4.1.4 around parsing.

[sip]

I have already posted 4.1.4 ugrade resulted in 406 errors which on 4.1.3 never happened. So i have downgraded to 4.1.3. Seems 4.1.4 has some issues.

On CentOS 5.x
cPanel/WHM.

Regards

[sysmesh]

Yeah. I hope they solve it soon.

[webizen]

please post more details of 406 error if any from error log (e.g. /usr/local/apache/logs/error_log).

I have already posted 4.1.4 ugrade resulted in 406 errors which on 4.1.3 never happened. So i have downgraded to 4.1.3. Seems 4.1.4 has some issues.

On CentOS 5.x
cPanel/WHM.

Regards

[sip]

However, here's more detail (not from logs):

4.1.3 works fine on all sites (commercial cms based).
When upgraded to 4.1.4 images being posted in body of article gives rise to 406 errors and the article gets saved without the image.

As a result of this had to downgrade to 4.1.3 where everything works fine.
Pl note that there's no change in any configuration done on server (except for upgrade to 4.1.4) so there's no other variable which could be causing this as only change that happens is Upgrade to 4.1.4 from 4.1.3

Currently running 4.1.3 (downgraded from 4.1.4) with no such error.

Regards

please post more details of 406 error if any from error log (e.g. /usr/local/apache/logs/error_log).

[mistwang]

Any one can reliably reproduce this problem with 4.1.4, please contact bug@litespeed..., we need to figure out what exactly causing this problem.

[sip]

Just sent an email wrt this post.

Regards

Any one can reliably reproduce this problem with 4.1.4, please contact bug@litespeed..., we need to figure out what exactly causing this problem.

[mistwang]

Please do force reinstall of 4.1.4, it should be addressed now.
Scan request body is enabled by default in 4.1.4, while it was disable in Apache and earlier release of LSWS.

[redstrike]

Hello, I got big problem with my site. Below is my top -c, litespeed eats up a lot of CPU. Does it because someone hotlink my large static files? I usually got "Cannot display error after a few successful hit". This is very annoy. Does my bottneck is CPU Bound?

top - 12:38:30 up 54 min, 1 user, load average: 2.39, 2.24, 2.10
Tasks: 75 total, 3 running, 72 sleeping, 0 stopped, 0 zombie
Cpu(s): 16.7%us, 32.5%sy, 0.0%ni, 50.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 786432k total, 409056k used, 377376k free, 0k buffers
Swap: 131072k total, 0k used, 131072k free, 0k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
5171 apache 4 -19 11812 6500 1628 R 96.8 0.8 11:03.69 litespeed
3572 root 15 0 10196 2960 2368 R 1.0 0.4 0:13.60 sshd
1 root 15 0 2156 664 572 S 0.0 0.1 0:00.22 init
1114 root 15 -4 2260 556 344 S 0.0 0.1 0:00.00 udevd
1204 root 15 0 22448 568 468 S 0.0 0.1 0:00.57 brcm_iscsiuio
1413 root 16 0 1812 572 480 S 0.0 0.1 0:00.03 syslogd
1463 root 15 0 7204 1060 660 S 0.0 0.1 0:00.00 sshd
1472 root 18 0 2832 864 696 S 0.0 0.1 0:00.00 xinetd
1482 root 19 0 3708 1308 1132 S 0.0 0.2 0:00.01 mysqld_safe
1508 root 15 0 3248 432 324 S 0.0 0.1 0:00.12 da-popb4smtp
1543 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.66 mysqld
1572 ftp 15 0 2888 1068 524 S 0.0 0.1 0:00.05 proftpd
1592 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.08 mysqld
1593 mysql 20 0 200m 43m 3476 S 0.0 5.7 0:00.00 mysqld
1594 mysql 16 0 200m 43m 3476 S 0.0 5.7 0:00.00 mysqld
1595 mysql 17 0 200m 43m 3476 S 0.0 5.7 0:00.00 mysqld
1596 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.07 mysqld
1632 root 18 0 4488 1112 560 S 0.0 0.1 0:00.02 crond
3512 xfs 18 0 3216 1000 720 S 0.0 0.1 0:00.00 xfs
3549 root 18 0 5684 700 424 S 0.0 0.1 0:00.00 saslauthd
3550 root 18 0 5684 440 164 S 0.0 0.1 0:00.00 saslauthd
3559 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.51 mysqld
3560 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.56 mysqld
3561 mysql 16 0 200m 43m 3476 S 0.0 5.7 0:00.72 mysqld
3562 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.97 mysqld
3564 mysql 18 0 200m 43m 3476 S 0.0 5.7 0:00.94 mysqld
3565 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.26 mysqld
3566 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.05 mysqld
3567 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.17 mysqld
3568 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.22 mysqld
3576 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.19 mysqld
3579 root 20 0 2772 532 444 S 0.0 0.1 0:00.00 nc
3580 root 20 0 2772 540 448 S 0.0 0.1 0:00.00 nc
3584 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.99 mysqld
3585 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.29 mysqld
3586 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.10 mysqld
3588 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.81 mysqld
3590 mysql 18 0 200m 43m 3476 S 0.0 5.7 0:12.02 mysqld
3595 mysql 17 0 200m 43m 3476 S 0.0 5.7 0:01.14 mysqld
3597 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.94 mysqld
3599 mysql 18 0 200m 43m 3476 S 0.0 5.7 0:01.23 mysqld
3611 nobody 15 0 9176 1348 940 S 0.0 0.2 0:00.12 directadmin
3644 named 20 0 50344 3472 1904 S 0.0 0.4 0:00.03 named
3655 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.02 mysqld
3656 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.19 mysqld
3658 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.83 mysqld
3660 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.20 mysqld
3662 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.43 mysqld
3664 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.98 mysqld
3680 mysql 16 0 200m 43m 3476 S 0.0 5.7 0:00.92 mysqld
3683 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:00.85 mysqld
3684 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.03 mysqld
3685 mysql 16 0 200m 43m 3476 S 0.0 5.7 0:00.98 mysqld
3687 mysql 16 0 200m 43m 3476 S 0.0 5.7 0:00.86 mysqld
3689 mysql 15 0 200m 43m 3476 S 0.0 5.7 0:01.59 mysqld
3792 nobody 15 0 9176 572 164 S 0.0 0.1 0:00.00 directadmin
3877 nobody 15 0 9176 572 164 S 0.0 0.1 0:00.00 directadmin
3890 nobody 15 0 9176 572 164 S 0.0 0.1 0:00.00 directadmin
3930 nobody 15 0 9176 572 164 S 0.0 0.1 0:00.00 directadmin
3932 nobody 15 0 9176 572 164 S 0.0 0.1 0:00.00 directadmin
5169 root 0 -19 7328 2140 1472 S 0.0 0.3 0:00.11 litespeed

[NiteWave]

please take a screenshot of real-time stats.

[redstrike]

I have attached the the screenshot of Realtime Stats.

[NiteWave]

the picture not clear

[redstrike]

the picture not clear

Hi NiteWave,

It seems that the bottneck is disk I/O for streaming media. And another sites are trying to use my media url for streaming on their site, although i was enable Hot-Link Prevent. But a lot of "Not Found" requests still hits server and consume some resources. So, that's why one LiteSpeed instance was overload to serve a lot of media files and handle requests which come from outside.

[NiteWave]

but iowait showed in "top -c" is 0 -- 0.0%wa

[redstrike]

I think vmstat will be better show the case. I used the 2-CPU trial license last 2 months (that's time i didn't know about disk I/O), and i found that 2-CPU license wasn't help much in my case, on a small VPS with a limited computing power. The fact shows that, i don't usually used up max 150 connections before the disk I/O occurs.

[root@server ~]# vmstat 2
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
-
r b swpd free buff cache si so bi bo in cs us sy id wa st
1 1 0 396148 0 0 0 0 82067 13873 0 5796 5 7 52 36 0
0 1 0 391088 0 0 0 0 812 12 0 3552 6 1 61 31 0
0 1 0 390188 0 0 0 0 1036 14 0 4167 5 2 59 33 0
1 0 0 392512 0 0 0 0 990 240 0 3874 4 7 64 26 0
0 1 0 395064 0 0 0 0 532 102 0 4299 10 17 57 16 0
0 1 0 395064 0 0 0 0 180 2 0 3017 1 1 50 48 0
1 0 0 395032 0 0 0 0 1048 4 0 4616 16 23 58 3 0
1 0 0 397088 0 0 0 0 462 2 0 3432 16 30 51 3 0
0 1 0 397120 0 0 0 0 574 2 0 2854 16 31 49 3 0
0 1 0 397120 0 0 0 0 124 0 0 2318 0 0 50 50 0
0 1 0 397120 0 0 0 0 126 0 0 2820 0 0 50 50 0
0 1 0 390324 0 0 0 0 354 30 0 3564 5 9 49 37 0
3 0 0 390300 0 0 0 0 564 4 0 4214 17 19 53 10 0
1 0 0 392792 0 0 0 0 252 2 0 3962 13 15 55 16 0
1 0 0 392528 0 0 0 0 630 4 0 3801 18 29 43 10 0
0 1 0 395060 0 0 0 0 128 2 0 4199 11 17 49 23 0
0 1 0 400608 0 0 0 0 376 0 0 3934 7 10 55 28 0
1 0 0 400880 0 0 0 0 508 230 0 5083 11 20 46 22 0
0 1 0 400880 0 0 0 0 638 96 0 3117 11 25 48 16 0
1 0 0 400832 0 0 0 0 678 4 0 3639 14 21 46 19 0
1 0 0 400816 0 0 0 0 364 2 0 3876 15 29 49 7 0
1 0 0 400912 0 0 0 0 576 4 0 3413 7 14 49 30 0
1 0 0 400912 0 0 0 0 650 2 0 3566 15 32 49 4 0
1 0 0 400636 0 0 0 0 106 2 0 3371 13 23 43 20 0
0 1 0 400636 0 0 0 0 284 0 0 3471 3 6 49 42 0
0 1 0 400068 0 0 0 0 626 6 0 4533 12 15 44 30 0
1 0 0 400068 0 0 0 0 388 8 0 3670 13 26 57 4 0
1 0 0 400100 0 0 0 0 602 212 0 3649 16 29 50 5 0
2 0 0 400356 0 0 0 0 512 46 0 4242 17 27 44 12 0
2 1 0 400356 0 0 0 0 514 4 0 4107 13 27 47 13 0
1 0 0 400356 0 0 0 0 1020 2 0 3757 15 25 48 12 0
0 1 0 400356 0 0 0 0 274 2 0 3537 12 27 50 11 0
0 1 0 400356 0 0 0 0 0 0 0 3662 0 0 50 50 0
3 0 0 400580 0 0 0 0 500 2 0 3670 11 14 39 37 0
1 0 0 401372 0 0 0 0 456 4 0 4747 12 24 54 10 0
1 0 0 401372 0 0 0 0 736 4 0 4539 8 16 49 27 0
0 2 0 400860 0 0 0 0 820 28 0 3996 9 16 48 27 0
1 0 0 400820 0 0 0 0 646 2 0 5343 13 22 42 22 0
0 1 0 400824 0 0 0 0 164 146 0 5081 9 20 48 23 0
2 0 0 400396 0 0 0 0 604 72 0 4614 8 11 51 30 0
1 0 0 401104 0 0 0 0 756 58 0 2687 6 11 49 34 0
0 1 0 400848 0 0 0 0 380 108 0 3217 7 14 47 32 0
1 0 0 400848 0 0 0 0 592 58 0 3217 4 7 50 39 0
0 1 0 400848 0 0 0 0 884 6 0 3152 7 13 51 29 0
1 0 0 400844 0 0 0 0 1060 4 0 4600 14 24 52 9 0
1 0 0 400876 0 0 0 0 636 2 0 2409 12 23 57 8 0
0 1 0 401108 0 0 0 0 828 30 0 2704 7 11 67 15 0
0 0 0 400836 0 0 0 0 378 2 0 3917 10 13 72 5 0
0 1 0 400840 0 0 0 0 722 6 0 2686 5 10 61 24 0
2 0 0 399864 0 0 0 0 908 106 0 2848 5 3 54 38 0
0 0 0 400312 0 0 0 0 470 56 0 2514 1 2 58 39 0
0 1 0 400336 0 0 0 0 858 60 0 2727 0 1 51 48 0
0 1 0 399704 0 0 0 0 778 42 0 3212 1 1 62 36 0
1 1 0 401352 0 0 0 0 1052 10 0 3638 5 5 50 41 0
1 0 0 401352 0 0 0 0 1428 6 0 3437 6 11 64 18 0
0 1 0 401096 0 0 0 0 828 4 0 2725 9 16 55 20 0
3 0 0 401104 0 0 0 0 1238 6 0 3028 7 11 51 31 0
1 0 0 400804 0 0 0 0 1174 2 0 3325 5 6 82 7 0
0 0 0 400804 0 0 0 0 804 2 0 3869 4 7 80 8 0
1 0 0 400780 0 0 0 0 1082 6 0 3391 7 14 60 19 0
0 0 0 400776 0 0 0 0 818 264 0 2885 5 9 61 25 0
0 0 0 401108 0 0 0 0 746 6 0 3629 4 8 84 5 0
0 0 0 401108 0 0 0 0 754 0 0 3314 0 0 97 2 0

[NiteWave]

if so, you can enable AIO instead of sendfile to see if any improvement.

Server->Tuning->Use Asynchronized disk I/O (AIO)

[redstrike]

if so, you can enable AIO instead of sendfile to see if any improvement.

Server->Tuning->Use Asynchronized disk I/O (AIO)

Thanks NiteWave, i will try AIO when i have owned a license. Maybe, it wouldn't help because the limit of VPS itself. So i am going to add more node.

[redstrike]

if so, you can enable AIO instead of sendfile to see if any improvement.

Server->Tuning->Use Asynchronized disk I/O (AIO)

You mean when we enable AIO, we must disable "Use sendfile()" to allow AIO starting to work? I have tried 2-CPU trial license, but that time i didn't disable sendfiles option and the result wasn't better.

After that trial time, i understood that i got big disk I/O problem when other sites was using my media url to stream on their site. And come to now, i feel that it is difficult to access realtime stats page while peak hours so that is very annoy, viewing server logs is difficult too.

LiteSpeed is a great web server, i hope via my case. LiteSpeed Team can figure something out and optimize it far better.

[mistwang]

sendfile should be enabled along with AIO.
Maybe you are using PHP script to streaming files, it is low efficient, if so, you should consider using internal redirect feature.
http://www.litespeedtech.com/support/wiki/doku.php?id=litespeed:wiki:feature:internal_redire ct

[redstrike]

sendfile should be enabled along with AIO.
Maybe you are using PHP script to streaming files, it is low efficient, if so, you should consider using internal redirect feature.
http://www.litespeedtech.com/support/wiki/doku.php?id=litespeed:wiki:feature:internal_redire ct
I am not sure i am using PHP script to streaming files or not. My scripts create a playlist file (asx format) with full URL to media file. Can you check for it me? http://vn2rap.com/m/#Play,20200 --- http://vn2rap.com/m/asx.php?type=1&id=20200

I am using PHP. How can i use internal redirect?

[NiteWave]

the 2 URLs not accessible or empty page

[redstrike]

the 2 URLs not accessible or empty page

This is the main thing: http://vn2rap.com/m/#Play,20200
Player streaming asx create by this link: http://vn2rap.com/m/asx.php?type=1&id=20200 it doesn't show directly on browser, you should use some downloader to download. It will show it's content.

Does it shows that: "cannot display ..." ? You should try to refresh after a coupe seconds. This issues is what i have mentioned. In cases, do you need to access SSH, and litespeed cp to messure my problem?

[NiteWave]

please PM the access info. otherwise, don't know exactly what this issue is

[redstrike]

please PM the access info. otherwise, don't know exactly what this issue is

I sent my root info via PM to you, did you receive it?

[NiteWave]

received.
it's a OpenVZ container.
~>date;cat /proc/user_beancounters;date
Tue Sep 6 13:06:46 ICT 2011
Version: 2.5
uid resource held maxheld barrier limit failcnt
244074: kmemsize 11820364 28828390 2147483646 2147483646 0
lockedpages 0 8 1000 1000 5
privvmpages 97081 166263 196608 196608 0
shmpages 11989 52035 98304 98304 0
dummy 0 0 0 0 0
numproc 111 304 500 500 0
physpages 26472 75044 0 2147483647 0
vmguarpages 0 0 196608 196608 0
oomguarpages 26810 75045 196608 196608 0
numtcpsock 45 1000 1000 1000 7035
numflock 21 137 1000 1000 0
numpty 1 3 500 500 0
numsiginfo 53 254 1000 1000 0
tcpsndbuf 3144432 10843328 3145728 4194304 79847400259
tcprcvbuf 261776 5311712 2097152 3145728 0
othersockbuf 94376 4708440 2097152 3145728 5084
dgramrcvbuf 0 16944 80530432 113298432 0
numothersock 55 626 5000 5000 0
dcachesize 4688185 7027826 9216000 9216000 0
numfile 2142 4118 24000 24000 0
dummy 0 0 0 0 0
dummy 0 0 0 0 0
dummy 0 0 0 0 0
numiptent 38 200 1500 1500 0
Tue Sep 6 13:06:46 ICT 2011
~>

looking at the failcnt column, there are a lot of failures.
please increase barrier/limit, especially tcpsndnif at host first.
let's see if any improvement.

[redstrike]

received.
it's a OpenVZ container.
~>date;cat /proc/user_beancounters;date
Tue Sep 6 13:06:46 ICT 2011
Version: 2.5
uid resource held maxheld barrier limit failcnt
244074: kmemsize 11820364 28828390 2147483646 2147483646 0
lockedpages 0 8 1000 1000 5
privvmpages 97081 166263 196608 196608 0
shmpages 11989 52035 98304 98304 0
dummy 0 0 0 0 0
numproc 111 304 500 500 0
physpages 26472 75044 0 2147483647 0
vmguarpages 0 0 196608 196608 0
oomguarpages 26810 75045 196608 196608 0
numtcpsock 45 1000 1000 1000 7035
numflock 21 137 1000 1000 0
numpty 1 3 500 500 0
numsiginfo 53 254 1000 1000 0
tcpsndbuf 3144432 10843328 3145728 4194304 79847400259
tcprcvbuf 261776 5311712 2097152 3145728 0
othersockbuf 94376 4708440 2097152 3145728 5084
dgramrcvbuf 0 16944 80530432 113298432 0
numothersock 55 626 5000 5000 0
dcachesize 4688185 7027826 9216000 9216000 0
numfile 2142 4118 24000 24000 0
dummy 0 0 0 0 0
dummy 0 0 0 0 0
dummy 0 0 0 0 0
numiptent 38 200 1500 1500 0
Tue Sep 6 13:06:46 ICT 2011
~>

looking at the failcnt column, there are a lot of failures.
please increase barrier/limit, especially tcpsndnif at host first.
let's see if any improvement.

I have sent ticket to host, i will reply when barrier/limit and tcpsndnif has been tweaked. You can continue to monitor it as long as you want.

Thank you so much, NiteWave!

[redstrike]

... The bottneck is the VPS provider limited my banwidth usage to 4 MB/s (normally my site used 6 MB/s), everything will be drop when it over the limit :(.

Thanks NiteWave, if you didn't find out that, i wouldn't know the situation. Adding more node for load balancing is my solution now.

[NiteWave]

while everything drop, CPU usage of litespeed process up to 100% -- so the reason is the bandwidth limit. this result will benefit other uesrs. Thanks for the feedback. I'd mark this thread "solved".