Author: Sahil Suri

Introduction In order to maintain overall operating system stability it is important to check that directories/file systems being used as temporary storage space by applications should get full. This is because a temporary file system out of space could cause a server to go into hung state and under extreme circumstances even a kernel panic might occur.  Have you ever wondered why most files inside the /tmp directory get deleted over some time if they are left unused? If you have then this article is for you. In this article we will explain how and why the /tmp directory gets emptied over a period of time on Linux systems. We will explaining the concept on Centos 6/RHEL 6 systems. The mechanism is different in case of Centos 7/RHEL 7 systems. A program named tmpwatch is responsible for periodically cleaning up the /tmp and /var/tmp directories on Centos 6/RHEL 6 systems. tmpwatch recursively removes files which haven’t been accessed for a given time. Normally, it’s used to clean up directories which are used for temporary holding space such as /tmp. It does not follow symbolic links in the directories when it’s cleaning up the directory, will not switch file systems, skips lost+found and directories owned by the root user. The tmpwatch program should be installed on the system by default and you confirm the same by performing a query on...

Introduction We explained how to install VirtualBox on a Centos 7 machine in an earlier article wherein we ran into an issue during the install itself and were unable to start the service. In this article, we will share the diagnostic steps and the consequent resolution after which we were finally able to start the service and use the VirtualBox application.   Issue On installing VirtualBox from Oracles’ official repository we received the following message This system is currently not set up to build kernel modules. Please install the Linux kernel "header" files matching the current kernel for adding new hardware support to the system. The distribution packages containing the headers are probably: kernel-devel kernel-devel-3.10.0-123.el7.x86_64 This system is currently not set up to build kernel modules. Please install the Linux kernel "header" files matching the current kernel for adding new hardware support to the system. The distribution packages containing the headers are probably: kernel-devel kernel-devel-3.10.0-123.el7.x86_64 I tried to start the vboxdrv service but the startup failed and given below is the systemctl status output [root@linuxnix ~]# systemctl status vboxdrv.service vboxdrv.service - VirtualBox Linux kernel module Loaded: loaded (/usr/lib/virtualbox/vboxdrv.sh; enabled) Active: failed (Result: exit-code) since Wed 2018-09-19 12:25:08 EDT; 10s ago Process: 58858 ExecStart=/usr/lib/virtualbox/vboxdrv.sh start (code=exited, status=1/FAILURE) Sep 19 12:25:08 linuxnix vboxdrv.sh[58858]: vboxdrv.sh: Starting VirtualBox services. Sep 19 12:25:08 linuxnix vboxdrv.sh[58858]: vboxdrv.sh: Building VirtualBox kernel modules. Sep 19 12:25:08 linuxnix...

Introduction Oracle VM Virtualbox popularly referred to as Virtualbox is a is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers, it is also the only professional solution that is freely available as Open Source Software under the terms of the GNU General Public License (GPL) version 2. When we describe VirtualBox as a “virtualization” product, we refer to “full virtualization”, that is, the particular kind of virtualization that allows an unmodified operating system with all of its installed software to run in a special environment, on top of your existing operating system. This environment, called a “virtual machine”, is created by the virtualization software by intercepting access to certain hardware components and certain features. The physical computer is then usually called the “host”, while the virtual machine is often called a “guest”. Most of the guest code runs unmodified, directly on the host computer, and the guest operating system “thinks” it’s running on real machine. VirtualBox can be installed on host operating systems, including Linux, Windows, Solaris, OS X, and OpenSolaris. From version 2.0 VirtualBox supports 32 and 64bit host and guest operating systems. If you want to install 64bit guests then your processor must support hardware virtualization and the host operating system must be 64bit as well. Hardware...