Troubleshooting is a form of problem solving, often applied to repair failed products or processes.

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18
votes
7answers
37k views

Why is USB not working in Linux when it works in UEFI/BIOS?

For background I have just built a new machine with modern hardware including: AMD FX-8350 Gigabyte GA-990FXA-UD3 motherboard 16GB RAM NVidia GTX 650 Ti Kingston SSD Given that, I tried to install ...
16
votes
3answers
20k views

Linux network troubleshooting and debugging

From time to time Linux and Unix users faced with various network problems. Many of these problems are presented here and at some others troubleshooting forums, but the are very concrete and contains ...
14
votes
2answers
2k views

Why do my identically prepared USB sticks differ in one byte?

I have two identical USB sticks (TrekStor 16GB) prepared as following with the c't bankix image. Preparation using GParted: Deleted the existing partition Created a new DOS partition table ...
11
votes
3answers
4k views

Trim with LVM and dm-crypt

I tried to setup TRIM with LVM and dm-crypt on ubuntu 13.04 following this tutorial: http://blog.neutrino.es/2013/howto-properly-activate-trim-for-your-ssd-on-linux-fstrim-lvm-and-dmcrypt/ See the ...
7
votes
3answers
1k views

Best practise to diagnose problems [closed]

As Linux/Unix users, we run into problems frequently. And after long hours of problem solving, we develop the skill of debugging. Now, what are good principles, methods or best practises when trying ...
7
votes
1answer
369 views

Where should I look for error messages after a freeze-up and reboot in Linux?

I was forced to shutdown (using the power button) and reboot after my laptop froze with just a black screen. After such an incident, where should I look for error messages etc. that might indicate ...
7
votes
2answers
8k views

console-kit-daemon Hogging CPU and RAM

We have a system that's been a bit sluggish. top reports that console-kit-daemon takes anywhere from 18-30% CPU and about 50% memory. There are only two users logged in, one on X and one via ssh. Any ...
6
votes
1answer
1k views

What would cause “crossover” between two USB2 webcams when using motion?

I am using the Motion package for linux to act as a security system with two Microsoft LifeCam HD-5000 webcams. In general it's working very well but I'm experiencing a weird issue. Every now and then ...
6
votes
1answer
5k views

Why can I not see some files in my USB stick on Windows that I can see on Linux?

I'm having a little problem with my USB stick. There are files and folders on the USB stick I can see and manipulate on my Linux machine (Fedora 20) but some of those files and folders appear nowhere ...
6
votes
2answers
2k views

Debugging hanging bash process

After some bad performance today, I checked top: 1 PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 14229 myuser 20 0 8776 5264 1684 R 99 0.2 1383:47 bash 98-100% ...
6
votes
3answers
4k views

Remote-Accesible Live-Distribution (aka Live CD)

I'm looking for a live distribution (Live CD or the likes) which comes - per default - with sshd running at startup. I want to check the components of my laptop whose graphics has died ...
6
votes
2answers
775 views

Suggestions needed to debug why ps -ef gets stuck

A few of my processes consume 100% cpu. I'm trying to figure out which scripts are causing it I tried running strace ps -ef: open("/proc/PID/status", O_RDONLY) = 6 read(6, "Name:\textract\nState:\tR ...
5
votes
2answers
1k views

User data in evince and cups

Some days ago my evince stopped printing. After reinstalling it and trying different versions without success I figured out that it works from other user accounts on the same box. So which files ...
4
votes
2answers
205 views

My /var/log/ is mysteriously filling up GBs in minutes! Any cure before I re-install Debian 7?

Good morning, fellow *nix enthusiasts! I have been using Debian 7 for a while now and after a recent upgrade I noticed I constantly kept running out space on my root partition. I mean to the point ...
4
votes
2answers
4k views

Mate desktop breaks with no panels and tens of caja windows on user switching?

I'm using Sabayon GNU/Linux with Mate-Desktop. I have my computer set up for multiple users so my girlfriend and the kids can use it too. ~ $ uname -a Linux 3.9.0-sabayon #1 SMP Thu Jun 27 07:53:45 ...
4
votes
2answers
894 views

How to troubleshoot the old X applications working incorrectly on modern X servers?

I have an old X application provided as a part of a complicated signal processing package. The application resides on the display-less server, and clients having different X-servers connect to it. On ...
3
votes
2answers
23 views

Can resource over-utilization actually cause users to be unable to SSH to Linux?

The night support guys where I work have a tendency to reboot machines citing the fact that they can't ssh in and figure out what's going on in the first place. It's pretty much against company ...
3
votes
1answer
109 views

How to interpret the following pattern of uptime data?

I have a small web server running mysql and wordpress which after a while appears to stop processing web requests. I can't even log into the server via ssh as ssh client times out when trying to ...
3
votes
1answer
2k views

Trouble booting CentOS

I switched from an Ubuntu to the CentOS yesterday. But it seems I have messed my installation somehow, since OS will only start correctly if the USB with the installation is plugged in. Long story: ...
3
votes
1answer
3k views

Why does my mouse stop working a short time into my session?

Running Easy Peasy 1.6 clean installation. Hardware - EEE PC 900-HA. About 10 or so minutes into a new session after a reboot my mouse will stop working. It will still move the pointer, but it will ...
3
votes
1answer
175 views

How to get correct scan codes for my laptop keyboard without pressing a key?

I have a problem with the keyboard of my laptop which doesn't work properly anymore. However I have full control of the laptop via ssh. The problem is that I use a self encrypting disk (Samsung 840 ...
3
votes
2answers
8k views

No MAC corresponding to IP in `arp` table: how to troubleshoot?

I've got a Debian 7 linux machine and a TP-link MR3020 router attached to it via ethernet cable at eth0 interface, working in WISP mode meant to make it a client rather than an access point: I also ...
3
votes
1answer
192 views

Slow ecryptfs mount

If I create an encrypted share (internally done via ecryptfs) on a synology disk station DS109 (DSM 4.1), mounting is very slow (approx 40 seconds). It doesn't matter if I do it via the ...
3
votes
1answer
565 views

good unix troubleshooting book [closed]

I've been trying to learn *nix and I think I'm doing pretty good as far as basic commands, and I think I understand a lot of the "monitoring" type commands etc... in short, I think I'm doing okay with ...
3
votes
2answers
355 views

Unblanking a Linux Terminal Display

I am running an Ubuntu Server that boots to the console. After a long wile, the screen goes blank and I cannot type or unblank the screen. Even the caps lock / num lock do not change states. I am ...
2
votes
2answers
58 views

How can I determine which service run during bootup is responsible for a certain behaviour?

On my Fedora 14 system, some strange bind mounts have appeared in the list of mounts. They appear on every bootup. I can unmount them with umount -l, but I would like to find which package is mounting ...
2
votes
1answer
188 views

Diagnose unplanned shutdowns

I have a problem with a server that is shutting down for some unknown reason. I check the logs each time it happens and cannot find anything of particular interest which would suggest why its going ...
2
votes
1answer
3k views

Gnome 3 “broken” after upgrades, kind of looks like gnome 2 . . .?

I'm running debian wheezy ( testing ) and after some upgrades my gnome 3 is broken. It's not exactly broken, but it's completey different. Almost like it's no longer actually gnome 3; most of the UI ...
2
votes
2answers
4k views

How do I reinstall software properly in Debian?

I got myself into trouble with mysql on debian lenny (details). I tried these commands: dpkg-reconfigure mysql dpkg --purge mysql-server apt-get install mysql-server mysql_install_db and variants ...
2
votes
5answers
171 views

Difficulty setting up iptables

I'm very new to *nix operating systems, and I'm having some trouble which I believe is because of misconfiguration of the iptables firewall. My server has SSH running on port 22, and server software ...
2
votes
4answers
549 views

Is there a way to circumvent normal installation proceedures and manually install (M1400 Motion Computing Tablet)

TLDR version Can I install Linux by booting the Live CD and then doing a dd if=/ of=/dev/hda? Can I somehow install Linux by copying files off of the installing ISO directly onto the harddisk drive? ...
2
votes
1answer
62 views

How might I detect memory errors if I do not have root or physical access to a Linux system?

The background to my question is as follows. I currently rent a virtual private server from a major hosting company, which I use to run a minecraft server. I have a suspicion that there may be bad ...
2
votes
1answer
3k views

how to troubleshoot a network adapter on an AIX 4.3.3 machine

I'm trying to brush up my skills on AIX. I have an ancient RS/6000 43P-133 which I'm trying to resurrect before investing in anything more sophisticated. I used to do automation and scripting on AIX ...
2
votes
1answer
43 views

Restarting all the network in Ubuntu after hibernating

When my Ubuntu 14.04 machine awakes from hibernation, sometimes the network is disable and enabling it does not make it work again. Running sudo service network-manager restart alone does not solve ...
2
votes
1answer
738 views

How to boot Chromium OS verbosely?

I'm attempting to boot the latest Chromium OS 32-bit build from this site. Whilst I'm currently experiencing a typical installation issue (stuck at a black screen after initial loading screen), not ...
2
votes
1answer
576 views

Problem with java3d

I want to play this java simulation: http://www.compadre.org/OSP/items/detail.cfm?ID=9640 in java 3d mode on a linux (ubuntu) system. But it doesn't work. If I switch to java 3d-mode it complains ...
2
votes
1answer
161 views

Missing entries from messages file

I have a CentOS server that has been working well until recently. The virtualized instance of the server encountered some type of issue earlier today and required it to be hard rebooted in order for ...
2
votes
0answers
200 views

Why am I losing audio on VLC when playing HQ videos?

I am having a problem with VLC when I play HQ videos (720p and higher): when I try to look for a particular scene (say I am playing a movie and want to get to go to 30 minute mark) the sound goes off. ...
2
votes
1answer
143 views

Troubleshooting internet connectivity

Recently I see that I often lose internet connectivity on my Linux machines. I am starting to think that it may be a router problem, but I have no idea to check if this is indeed the problem. ...
2
votes
0answers
485 views

can't open netbeans IDE in Fedora 17

my linux version is: Fedora 17 I installed Netbeans IDE 7.1.2 and it was working fine, but now, when I try to open it, nothing happens after double clicking on it. I think updating the kernel may be ...
1
vote
1answer
236 views

Accidentally set /lib permissions to 644

Long story short, I've got an Ubuntu server box that was recently compromised (I believe through a known exploit of an older version of Tomcat, which has already been updated). Part of the exploit ...
1
vote
3answers
630 views

Troubleshoot SSH connection problem

I am looking for tips on how to troubleshoot a problem with connecting to a new server via SSH. I am trying to connect using private-key authentication, where SSH uses my local private key to ...
1
vote
1answer
59 views

Is there a general rule for tracking an error?

I would like to start with an example here just to make it easy to convey my question. I have uncommented the following line from the /etc/pam.d/su file auth required pam_wheel.so use_uid thus ...
1
vote
1answer
31 views

Language variable missing after the update

It appears that language variable is missing after our recent update to our Linux servers. We are running Redhat 5 on them. Is there anyway update can remove variables? The env output shows nothing ...
1
vote
2answers
872 views

Backup to a synology NAS with bup

I am trying to make a remote backup to my Synology NAS (DSM 4.1) using bup. I compiled bup on my NAS from source, did there: BUP_DIR=/volume1/public/Backups/bup bup init Initialized empty Git ...
1
vote
1answer
463 views

Killed `rm` and `cp` on nfs share

I am just testing an rsnapshot installation on my laptop which should backup to a NAS mounted via nfs on my laptop. On one test rsnapshot died with a cp -al problem (i.e. a problem with hard links) ...
1
vote
2answers
280 views

How come I suddenly don't have any audio?

Just a few minutes ago my sound was working, and then it stopped! I suspect it was caused by me checking out some video editors. How do I go about troubleshooting this? What I've so far tried: I ...
1
vote
1answer
20 views

sendmail attachment is empty

I am trying to include an attachment to my sendmail eml file. The current eml file (order.eml) has the following contents From: Sender <sender@email.com> To: client@email.co.za Subject: Report ...
1
vote
1answer
376 views

Can I do reverse traceroute?

Is it possible to do reverse traceroute ? This is very important for me to know, Why the websites are loading slow for my clients in certain area ? I have explained my problem here: (why i need ...
1
vote
1answer
99 views

traceroute / mtr from multiple locations, How can we do it ? (Or alternate way)

I have a website, recently due to some network issue, Most of my customers are reporting slow loading time of my website. When I reported this to my DataCenter, they are asking me to send the ping / ...