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Questions tagged [troubleshooting]

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

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88
votes
3answers
119k 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 they are very concrete and contains ...
76
votes
3answers
85k views

How to troubleshoot DNS with systemd-resolved?

How would you go about finding the DNS servers used by systemd-resolved, for troubleshooting purposes? Generally I can use dig and test the DNS servers shown in /etc/resolv.conf. (Or windows - ...
34
votes
8answers
143k 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 ...
23
votes
3answers
10k 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 ...
15
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 Formatted ...
10
votes
2answers
16k 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 ...
10
votes
2answers
57k 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 ...
9
votes
2answers
6k views

jetbrains-toolbox loads to a blank screen

For the last month or so, I've been attempting to get jetbrains-toolbox to work. It used to work (and is how I installed IntelliJ IDEA and Gogland.) When I went to update the IDEA I'm currently ...
9
votes
3answers
19k views

Chrony 3.1 refuses to sync with ntp server

I have 70 machine with CentOS 7.2 and chrony version 2.1.1 syncing perfect with my NTP server protocol v3. Recently I added 30 machines with CentOS 7.4 and chrony version 3.1, but these 30 machines ...
9
votes
4answers
13k views

Remote-Accessible 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 (card-...
8
votes
4answers
1k views

How can I track script which gives me “command not found” right after the login?

When I login, I have these messages: -bash: $'\r' : command not found -bash: $'\r' : command not found -bash: $'\r' : command not found It is quite clear that it is caused by Windows-style line ...
8
votes
3answers
5k 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 ...
8
votes
3answers
26k 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 ...
8
votes
2answers
3k 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 ...
7
votes
1answer
960 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
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 ...
7
votes
2answers
10k 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 ...
7
votes
2answers
7k 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
2answers
9k views

Startup Debian 10 error: networking.service loading failed

I've noticed that every time I turn on my PC, there is a line in red. My PC is pretty fast so I don't get to read the problem. I haven't experienced or noticed any problem with my system, but I'm ...
6
votes
1answer
4k views

Machine freezes once it hits swap space under heavy load

I encountered several crashes of my machine. Meanwhile, I can reproduce it when I start a program that fills up all memory. Once the system starts writing to the swap file, the system freezes and I ...
6
votes
2answers
33k 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 ...
5
votes
3answers
717 views

When using vi typing a “c” will delete a character

This also happens when copying and pasting. I am attempting to edit Go code and typing or copying and pasting "package main" comes out as "pkage main". No idea why I can't type a c. Pressing delete ...
5
votes
2answers
3k 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 ...
5
votes
1answer
3k views

Figure out which process forks too many threads

I have a process in a Linux installation that at some point has some kind of spike and passes the max allowed number of threads/processes allowed by the system. I found this by checking ps -elfT | wc -...
5
votes
3answers
24k views

How to diagnose SSH connection timeout issue?

I have a VPS running Debian 7, that I connect to using PuTTY from my Windows machine. Most of the time, PuTTY connects fine and I can log in fine. However, occasionally, PuTTY will report that ...
5
votes
2answers
62k views

How to detect, find and install a missing firmware [duplicate]

Context Today I installed Debian 8 on my HP Pavilion Notebook PC, during the installation (specifically during the network setting up), the the system prompted: Hardware needs non-free firmware to run,...
5
votes
0answers
7k views

RTNETLINK answers: File exists on Ubuntu Server 16.04

I have a fresh new install of Ubuntu Server 16.04. After installation, network connectivity was fine. I installed QuickBox, it's a seeding/torrent server software (https://quickbox.io). After the ...
4
votes
1answer
29k views

Manjaro won't boot after update, how to rescue?

I ran pacman -Syu yesterday and seeing quite a few updates, walked away from the computer while it was doing its thing. When I came back the lock screen had come up, and I was surprised to find that I ...
4
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: ...
4
votes
2answers
2k views

What causes permission to be denied for mounting rootfs, home, messeage queue, kernel file system, during boot?

My Fedora 27 x64 fails to boot after hard reset. It shows: Failed to mount POSIX Message Queue File System, Failed to start Remount and Kernel File Systems, Failed to mount Kernel Debug File System, ...
4
votes
2answers
7k 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
1answer
3k views

Connect to university WiFi using wpa_supplicant using ID and password

I recently re-installed my OS and forgot to back up my /etc/wpa_supplicant/wpa_supplicant.conf file, so I have been spending the day figuring out how to connect to the WiFi. I can connect to a public ...
4
votes
1answer
102 views

Launching applications from application launcher with “TZ=UTC” prefixed stopped working

I had a launcher for firefox with command TZ=UTC firefox. Suddenly it stopped working, I think after I did pacman -Syu (I only clicked again much later so it could be something else). I am using arch ...
4
votes
2answers
1k 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 ...
4
votes
0answers
979 views

Working out what is causing my machine to freeze

Background For a few years now, I have been having problems with my Xeon workstations freezing. For many things they have been lightning fast, but sometimes applications or even the desktop just ...
4
votes
0answers
2k views

How to figure out why Linux crashes

Every so often, my laptop will crash. The screen will freeze, including the cursor, the lock lights (caps lock and the like) will turn off if they were on, though my battery, power, and wifi lights ...
4
votes
0answers
1k views

Page gets cut in the half if I print from Chrome or Google Cloud but with Firefox doesn't

I'm setting up print server for custom thermal printer on RaspberryPi running Linux Debian and I have a strange problem. If I print a test page it prints OK, same with web page from Firefox, but when ...
3
votes
2answers
69 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
6k views

system-config-samba crash with could not open configuration file `/etc/libuser.conf'

OS: Linux Mint 18.3 Xfce 64-bit. I am trying to re-install samba, so far I've done: sudo apt-get install samba cifs-utils system-config-samba But when running the configuration GUI: sudo system-...
3
votes
1answer
14k views

kali linux - WiFi connected but can't surf the net

Preface #1 : I'm not using a Virtual Machine Preface #2 : during the installazion I skipped the Network Mirror step Preface #3 : I never used Linux before I have a laptop and I can connect ...
3
votes
2answers
13k 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 ...
3
votes
1answer
251 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
5k 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
5k views

Fedora 27 - Laptop won't suspend when closing lid

I am facing this rather bizarre situation. After shutting down my laptop by pushing the power button for a few seconds and powering it on again the "suspend when lid is closed" option isn't working. ...
3
votes
1answer
798 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
1answer
6k views

How do I troubleshoot ssh tunnels disconnection?

I am using SSH tunnels launched via autossh at boot on a device installed at remote locations. Up to now everything was working fine but yesterday the connection partly went down and autossh wouldn't ...
3
votes
1answer
353 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 web-...
3
votes
1answer
921 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
1answer
900 views

wifi slowdown after time, how to troubleshoot

I do not currently have access to the computer with the issue, to I am sorry if this question is a bit vague. I only need to know how to troubleshoot and not the actual solution. Right, I have a USB ...
3
votes
2answers
1k 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 ...

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