Technology Insights

Create A New Logical Volume In A Logical Volume Group With Space On A Linux Server

As noted in a previous article I have been working on a couple new Linux servers with a minimal install of CentOS on them. The /var, /usr, and / directories each were configured with 2GB of space within a logical volume group that has 1TB of space available. I first expanded the /var and /usr directory from 2GB to 20GB and then expanded the root, or /, directory from 2GB to 30GB. Once all three of these directories were expanded I next needed to create a new logical volume group and a partition to hold PostgreSQL data. Use the information below to create a new logical volume, format it with the ext3 file system, mount it, and configure it to be mounted automatically upon the next boot of the server.

Technology Insights

Expand A Partition That Is Part Of A Logical Volume Group While Server Is Running

I recently had a couple new CentOS Linux servers brought online at a colo that a company I work for uses. I had the colo do a very simple install of CentOS so I could handle the details without having to remove a bunch of packages we didn’t need. The servers have two one terabyte drives installed in a RAID 1 configuration which provides us with one terabyte of usable disk space and upon initial configuration had a logical volume group created with three logical volumes. Each of the logical volumes, which included /var, /usr, and /, only had two gigabytes of space so I needed to first expand those logical volumes and later will be creating a large logical volume used for database data. Below I describe expanding already existing logical volumes when there is room to grow in the logical volume group.

Technology Insights

Secure /tmp And /var/tmp Directories On CentOS Linux

A couple days ago a CentOS Linux server that I took over administration on had some mysterious files show up in the /tmp and /var/tmp directories. The files were placed in /tmp and /var/tmp by the apache user meaning there is some form of security hole in Apache, PHP, or one of the virtual hosts has an insecure application installed. Before looking into where the issue is I needed to lock things down so no applications could be executed from these directories in the future regardless of a security flaw in the future. Below are instructions on how to secure /tmp and /var/tmp.