As the amount of data we store continues to grow and grow, there is bound to become a time that you will need to resize your partitions to add more disk space. On our of my MySQL replication virtual servers, I created it initially with a 200GB disk. After moving all the data over, was wishing I would have had a bit more space. Good news is this can easily be done. I should note that I am using raw image files, not lvms, so there is a bit more work required.
I’m starting to work on replacing my CentOS 6 KVM server with a new CentOS 7 server. As much as I dislike CentOS 7, I’m trying to give it an honest try and make an honest attempt at learning. Working in the IT profession requires you to constantly adapt to change and learn new tech stacks. The problem I have is in CentOS 6 it was so easy to install KVM and set up a VM. CentOS 7 has been issue after issue. The most recent being the “Could Not Access KVM Kernel Module: Permission Denied” error.
It’s important to ensure system is kept virus-free, whether it be a server, workstation, or personal desktop computer. This tends to be easier with windows as we’re all familiar with the mountain of free and paid anti-virus programs available. You simply install one and it usually scans and monitors your system on its own. There are some options like this for Linux, but generally, as with any Linux system, you get many more configuration options to have it run how you want it to.
We ran in to this issue earlier this morning. One of our web servers started hit heavily with spam in the form of automated web posting bots. Since we are hosting forums, 99.9% of the load was centered around MySQL. To quickly stop the spam without having to wait an hour for MySQL to shut down, we ran a “killall -9 httpd” to stop all new incoming web requests and existing request from processing.
I recently replaced one of our cPanel DNS-only nameservers. Typically we run our DNS servers with 512MB of memory, because why would a simple DNS server need any more than that? I was shocked to see that cPanel, even the free DNS-only version, now requires 768MB of memory if you’re using CentOS7/RHEL6 or 1GB if you’re using CentOS7/RHEL7. If you are like us and are using a VPS to host your DNS, this can double your cost spent to maintain your DNS servers.
ClamAV is an open source anti-virus utility for Linux designed to detect viruses, malware, and our favorite – php script exploits. It does a great job at picking up php files containing backdoors, remote file managers, spam mailer bots, etc. We run this on all of our hosting servers daily. It is especially useful for detecting and removing files uploaded by the numerous exploitable Wordpress 3rd party plugins.