TROUBLESHOOTING

This category includes articles on trouble shooting various linux server issues.

How to Use BCC Kernel Tracing Tools for Linux Performance Analysis

ext4slower

Greetings, BCC is now available for Ubuntu and in this article we will be showing you its extended command line use to trace Linux systems for performance monitoring. The BPF Compiler Collection (BCC) is a toolkit for building kernel tracing [...]

Kashif Siddique 11:06 am

5 User Space Debugging Tools in Linux

invoking gdbinvoking gdb

By definition, debugging tools are those programs which allow us to monitor ,control and correct errors in other programs while they execute. Why should we use debugging tools? To answer this, there are various situations where we get stuck while [...]

B N Poornima 11:00 am

How to Fix a Broken Initrd Image in Linux

unmount

Today, we'll show you how you can fix your broken or accidentally deleted Initrd Image ie. Linux Kernel Image and GRUB Loader in your Ubuntu installed machine.  It should also work for Ubuntu derivatives as well as other distribution. Initrd is a [...]

Arun Pyasi 11:00 am

Fix Grub Filesystem Type Unknown Error on Centos/Redhat

Install GrubGrub Issue

GRUB is GRand Unified Bootloader, the default bootloader for Linux kernel based Operating Systems. If you have a dual boot system, like Windows and Linux, then you may have some issues with GRUB. If you install Windows after Linux installation, [...]

Bobbin Zachariah 6:41 pm

Fix Error - Locale: Cannot Set LC_ALL to default locale: No such file or directory

Question How to fix the error “locale: Cannot Set LC_ALL to default locale: No such file or directory”. Answer Locales are used in Linux to define which language the user uses. As the locales define the character sets being used [...]

Bobbin Zachariah 9:36 pm

How to Record/Log Failed Login Attempt in Linux

A system administrator needs to monitor any unusual activities on the system. An unauthorized user may try to access the system by trying out different passwords. A feature in Linux that can be used to monitor these failed login attempts is [...]

Bobbin Zachariah 8:13 pm

Linux Tcp Ports - How To Use Netstat and Iptables For Linux Troubleshooting

It is a well known fact that Linux/Unix systems are mostly used as servers and are often in connection to the internet. In such platforms, access is limited by ports used. The term 'port' means a number access point that [...]

Bobbin Zachariah 1:33 pm

How To Fix if Partition Table Entries not in Disk Order

The suggestion given below can help if your partition table is not in a proper disk order. From linux fdisk (fdsik /dev/), choose the advanced menu (by pressing x, afaik), then choose the entry for correcting partition ordering (press 'm' anytime [...]

Bobbin Zachariah 11:01 pm

How Linux Who & Last Command Helps for Root Cause Analysis

The last command is very important in linux as it helps in doing root cause analysis of the linux system. Assume that something is changed in the linux system, in this situation you are not sure who has made the changes. Using the 'last' [...]

Bobbin Zachariah 9:56 pm

How to Forcefully Unmount NFS Mounted Directory in Linux

NFS Linux

When you do an NFS mount, it sometimes shows busy status, in such case we need to perform force unmount in a graceful way. There are different ways and options we can try out if normal nfs unmount fails. Usually, [...]

Bobbin Zachariah 12:21 pm