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1answer
29 views

How to watch a file, who accesses or uses [duplicate]

I am looking forward a way to watch a file to get following information Which process does open, read, write it? When? Result. (e.g. can they write on it, or can they read it, etc.) Strace helps ...
0
votes
1answer
31 views

Tracing system calls is slow on a KVM VPS?

I run a website on a KVM VPS and I noticed that processes appear to run extremely slowly when being traced. For example, I ran ls on my home directory, which contains 72 files and directories. With ...
0
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0answers
25 views

Apache time-outs

I need some help to troubleshoot Apache time-outs. Could you please advise what tolls/steps I can use to troubleshoot this further? Details: CentOS 6.4 Apache 2.2.15 Requests just hang: $ curl -I ...
0
votes
0answers
122 views

How do I trace and troubleshoot recvfrom resource temporarily unavailable errors on an NFS Fat Client?

I'm running a few dozen Debian Wheezy diskless fat clients and, while trying to diagnose a slow performance web browser issue, I noticed IceWeasel(version 24.0-1~bpo70+1) was getting a ton of recvfrom ...
1
vote
0answers
43 views

Apache web server maxing out due to processes stuck at D status

I have a Apache 2.2.3 web server running on a 8 core VM with 8G Ram. During a load test, the web server stopped responding and load average went up to 1000. When I run Top command, I see a large ...
3
votes
3answers
202 views

MySQL hangs if connection comes from outside the LAN

I have a MySQL Server operating just fine if I access him from his local LAN (192.168.100.0/24). If I try to access hin from another LAN (192.168.113.0/24 in this case) it hangs for a really long time ...
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votes
0answers
25 views

MySQL sandbox strace option

Latest MySQL Sandbox version uses environment variable SBDEBUG to start mysql instances in debug mode, but i can't pass mysql --debug option. export SBDEBUG=d:t:O,/tmp/client.trace cd ...
1
vote
1answer
53 views

Debugging high CPU load when adding new domain inside server's control panel

When adding a new domain inside my server's control panel it takes much longer than usual since some time. CPU shows 100% usage on one core and strace reports something like this: poll([{fd=7, ...
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2answers
149 views

Troubleshooting SUDO Slowness with STRACE

I'm having trouble with sudo on some systems. It is taking anywhere from 15-30 seconds to complete a sudo command or to even login to the system. I ran an strace and can see where the delay is ...
1
vote
1answer
95 views

mongodb mystery crashes with sigkill under strace

I have a mongodb instance that seems to crash roughly once a day. I don't see any useful information in the mongo log file. All is well and then the process is just crashed with no additional ...
0
votes
1answer
83 views

strace vs. log4cxx performance hit?

I need to debug some issue on a production server, and I'm trying to decide whether to use strace or the log4cxx logging library; one crucial characteristic I need to know before, is which of the two ...
3
votes
0answers
217 views

mysql client slow login strace

I am experiencing an issue with slow connections/logins to a loaded mysql server, even when connecting via the unix socket file (CentOS 6.3). Queries are completing very quickly -- (0.00 sec) in this ...
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votes
4answers
5k views

Find out what high CPU usage apache process is actually doing?

Currently having a few issues with our server where, intermittently, we seem to get apache processes which just run and run, taking up 100% CPU. When running top, we see the following: PID USER ...
0
votes
2answers
289 views

Mysql killing the CPU with gettimeofday

I have a problem with mysql killing the CPU on a Debian Squeeze 64. This is a development machine on a VPS so I stopped all the other services, including apache2. The mysql version is 5.1.49. This is ...
0
votes
1answer
56 views

Trying to diagnose bottleneck for apache

I am trying to diagnose bottleneck for a apache(v 2.0.52) server using strace. It looks like call to poll is slowing the process. Below is one example poll([{fd=10, events=POLLIN}], 1, 120000) = 0 ...
0
votes
1answer
54 views

Interfacing strace with Process Name instead of PID

How do I implement a wrapper script pstrace in bash that changees the interface of [sudo] strace -c -p [PID] to [sudo] pstrace -c -p [PROCESS-NAME] similar to how killall [PROCESS-NAME] is ...
0
votes
2answers
486 views

Apache strace to hunt down a memory leak

We have a server with a memory issue: the server keeps allocating itself memory and doesn't release it. We're running Apache. I set MaxReqsPerClient to a really low value just so the threads don't ...
1
vote
1answer
596 views

How to resolve high CPU + excessive stat(“/etc/localtime”) and clock_gettime(CLOCK_REALTIME) calls

I've been experiencing really high CPU on a ruby on rails app (see stack below) and have been trying to diagnose the possible causes to no avail. Stack: ruby 1.9.3 rails 3.2.6 Apache/2.2.21 ...
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4answers
950 views

Apache process consumes too much CPU

I have an ubuntu apache/php server running php doing appx 100 hits/sec and a PHP cron running in the background. I get occasionally high CPU load on one of the Apache processes which stays high ...
0
votes
0answers
134 views

VPNC eats 100% CPU and strange output by strace

top - 21:02:03 up 28 days, 7:34, 1 user, load average: 1.00, 1.01, 1.05 Tasks: 95 total, 2 running, 93 sleeping, 0 stopped, 0 zombie Cpu(s): 1.4%us, 13.8%sy, 0.0%ni, 81.6%id, 3.2%wa, ...
1
vote
3answers
200 views

WSGI cannot access a file, but permissions are correct

I am debugging a problem where MoinMoin on CentOS is throwing a permissions error, but I can't track down where the problematic file / directory is. I ran strace -vp <pid> on the apache pid; ...
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0answers
262 views

Tracking down an elusive and slow anon_inode from lsof and Apache strace

Experiencing an intermittent issue with a LAMP application wherein Apache forks to its ServerLimit and grinds to a (near) halt. An strace on any httpd process shows numerous, slow epoll_wait calls. ...
0
votes
1answer
58 views

monitor processes in citrix

Where I work, We've been having trouble with certain applications mysteriously crashing/hanging in citrix; the primary culprits are IE8 and a certain .net-based industry specific app that we use. ...
3
votes
1answer
169 views

Why does strace open, read 512 bytes, and THEN fstat libncurses?

I've got the following strace output that I'm going through to teach myself a little more about the flow of programs. Here's the section that's confusing me: 16:08:02 open("/lib/libncurses.so.5", ...
3
votes
2answers
368 views

trace opening on a certain file

I know how to strace a certain program to see all the files it reads. I know how to see what processes are using a certain file at the moment. But is there a way to log all file opens. I want ...
1
vote
1answer
2k views

Java process (OpenDS) consumes all cpu (futex flood) - how to debug futex?

Today I noticed that my LDAP server (OpenDS) consumes 100% CPU on every available core. Fast diagnose showed me that there is a lot of ETIMEDOUT during the futex lock. How Can I debug it to figure ...
4
votes
1answer
566 views

Strace Apache process output showing 24 seconds wait?What can be the reason?

Performed strace on one one of the apache children and its showing 24 seconds between two system calls.How can i determine what is the cause of this behavior.It looks like both children are taking ...
3
votes
2answers
750 views

Why is my cron daemon is being killed every few minutes?

As of about a week ago, my cron daemon refuses to stay running. I'm using Debian 6 x64 on an OpenVZ virtual machine. Running something like pgrep cron shows that the daemon isn't running. I start the ...
10
votes
4answers
515 views

How would you simplify this command?

I'm quite new to strace / netstat / etc. I'm using this command to get a trace of the apache process handling my request (telnet), is there a way to simplify it a bit? sudo strace -o /tmp/strace -f ...
1
vote
2answers
699 views

puppet hanging or long time on rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0

In our setup, we manage our servers using puppet. Since a few days I saw the puppet client running very slow. When stracing the puppet process I get loads of rt_sigprocmask(SIG_BLOCK, NULL, [], 8) ...
0
votes
1answer
462 views

“yum clean” hangs - what to try next?

I run a number of CentOS servers. I was recently doing the occasional yum update but this failed on a handful of the servers. On most I have been able to move forward by doing: # yum clean all # rm ...
1
vote
1answer
230 views

Cant run programs under strace

I'm trying to run this simple program ls under strace and it wouldnt let me. Can you guys think of why this be the case? [jeffjose@skipper ~]$ strace ls strace: ptrace(PTRACE_TRACEME, ...): ...
1
vote
1answer
148 views

Long page loads - problems with DNS lookup?

I've noticed my web server takes a long time to load pages recently. Using Firebug, I realised it takes around 4s for the DNS lookup: Connecting: 304ms Sending: 0ms Waiting: 3.45s Receiving: 0ms I ...
1
vote
1answer
509 views

which pid to use to strace my apache

My apache2 is using running slowly. A single PHP file is takes long time to process. The server is live. I dont want to restart it. So I thought I attach strace to it and check whats happening. So ...
0
votes
1answer
75 views

secure rollback of updates

I'm again and again wondering why there isn't (or did I just not find it?) any tool which can reliably and effortlessly rollback changes done by updates. Let me take an update with apt on Debian as ...
1
vote
1answer
681 views

Attaching strace to 100% CPU Apache process - output

I am having a problem with Apache2 spawning processes that use 100% CPU. Attaching strace to one of such processes produces no output sometimes and sometimes gives this: 2672 17:18:07 poll([{fd=14, ...
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votes
2answers
526 views

Using strace effectively

Right now I'm dealing with a client's php based site that is somehow clogging up all of the available processes he has with his shared hosting provider. I'd like to prove to him exactly what and how ...
1
vote
2answers
142 views

How to analyze system calls when your disk is in read only and strace output is “Bus error”?

We have a HW problem with the disks, that made all the mount points to be read only. Output of dmesg: end_request: I/O error, dev sda, sector 15574609 sd 0:0:0:0: SCSI error: return code = 0x00040000 ...
2
votes
1answer
304 views

60 second php mail() delay through browser / Apache, but no delay through commandline

I am having a problem on my server when the PHP mail() function is being used in a browser, so through Apache. When the script, lets call it mailtest.php, is being called through a browser, there is ...
1
vote
2answers
2k views

How to set strace output characters string width to be longer?

Strangely i can't find it any where but when i stdout the output of strace into afile like this: strace foo.exe | & tee foo.log the out put is to short, how can i make the width longer?
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3answers
761 views

Remi Repo Mysql Server Not Starting

Executing the command to start the mysql service fails to start the mysql server. [root@localhost]# service mysqld restart Stopping mysqld: [ OK ] MySQL ...
3
votes
1answer
3k views

Strace poll, trying to diagnose bottleneck

I have no strace skill and knowlegde, but im trying to work through a problem where my clients application is awfully slow. And im trying to find out where the bottleneck / problem may lie. So I ran ...
1
vote
2answers
2k views

How do I run strace or ltrace on Tomcat Catalina?

Running ltrace isn't trivial. This RHEL 5.3 system has based on a Tomcat Catalina (servlet container) which uses text scripts to tie everything together. When I tried to find an executable here's the ...
1
vote
2answers
2k views

Monitor all newly spawned processes on a Linux machine

Sometimes a process comes and goes faster than I can ps aux, I tried watch -d -n0.1 "ps aux | tail" but again, that's restricted to 1/10th of a second. What I really want is to run a command and ...
0
votes
1answer
1k views

How to get PIDs waiting on a semaphore

If I strace a stuck process and see output of the form: [gaius@redhat64 bin]$ strace -p 18185 Process 18185 attached - interrupt to quit [ Process PID=18185 runs in 32 bit mode. ] semop(458760, ...
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1answer
510 views

Question About No Output From strace

I am using strace to see what certain processes are doing. I have an Apache process that seems to be running forever, taking up 97.8% of a core and almost 2GB of RAM. Now when I run strace on this ...
2
votes
1answer
2k views

Cannot Login as any user other than Root - permission denied

Help! I'm desperate :) I can't login as any user other than root. I'm on Ubuntu 10.04. Here's command output: root@pinky:~# adduser test Adding user `test' ... Adding new group `test' (1003) ... ...
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3answers
2k views

Monitor system CPU / system calls in Linux

I have a couple processes that are eating up a lot of system CPU time (as determined by looking at vmstat). Is there an easy way to find out what kind of system calls are being made? I know there ...
1
vote
1answer
110 views

Performance problem when launching GUI applications under gnome while connected to VPN

I'm experiencing a severe performance problem starting apps but only when connected to my office VPN. It appears to be related to gnome-session. I believe the following is the relevant strace from ...
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vote
2answers
1k views

ls -l freezes terminal locally and remotely

I've been reading other SF threads regarding ls not returning results or freezing and stalling terminal sessions and it appears they usually the fault of network problems. My problem however, occurs ...