Chances are that if you found this page through a Google search, you're probably looking for information on how addressing and routing actually works, without getting too deep into the complicated, underlying logic and binary math that serves as the foundationg for modern networking. At some point, I was looking for just this kind of information and ended up spending untold hours poring through texts trying to put it all together. So my goal with this article, is to save you as much time as possible. However, because it's so fundamental to routing, avoiding math entirely won't be possible.
A few articles back, we discussed server disk performance and how to quickly troubleshoot its issues.
Let's go over some of the basics, just to refresh your memory. Chances are, you were probably more concerned about space requirements than performance. If you server application works, then it's all good right? Well, not so fast.
Depending on what you're using, you’ll probably need to as much as 30-50% overhead storage than the raw amount of storage your data will EVER use just to maintain optimum disk performance. This is basically how ZFS, or most copy-on-write file systems, are set up. With more traditional storage solutions you have a few more options, but you still need to understand exactly how much room you have to work with.
If you have no idea how to go about figuring out how much overhead you need, well - that's why we wrote this article! Read on.
LVM - Logical Volume Manager - tools used to create and manage logical volumes.
When you attach a new hard drive to your Linux system, you'll likely need to create new particions and volumes. To do that, we're going to work with LVM; a system that came about to solve many of the problems of traditional partitioning which is too rigid by comparison. Being able to quickly create, increase or decrease, and copy a volume is not something available to us with the old particioning method.
We've written a tutorial before on a simple setup of OpenVPN on a server which allows clients to connect to your server quickly and easily. For the sake of simplicity, that article omitted to mention a a whole lot of other useful settings for OpenVPN. So let's fix that!
In our last article we covered basic MySQL server replication using the master-lave configuration, using it to create reserve database copies, and running resource intensive queries.
This configuration has a few relatively obvious limitations.
Rsnapshot is a simple and powerful backup tool used for local or remote file and directory synchronization over rsync with differential backup support. Why not just use rsync? With rsync you would have to write your own scripts, usually using with complex logic to handle file rotation, errors, resource consumption etc, while rsnapshot has already been written for you- it`s a well-known, stable, easy-maintenance utility that's already included in many Linux distributions by default.
In this article, I`ll show you how to make a remote backup of your files with rsnapshot and a remote sudo user.
In this article, we'll start with a simple setup of MySQL replication in a "master/slave" configuration. In this case, the primary MySQL server (master) will save all queries leading to changes in the database into binary logs that will, in turn, be sent over to replication servers (slaves) that are setup as read-only.
We've written before about installing and configuring MySQL server as well as touched on creating reserve backups of your databases. Creating a reserve copy is probably the simplest process to understand an implement for a budding sysadmin, and is a great place to start getting used to the basic objectives of MySQL server administration.
In one of our last articles, we talked about the cron job scheduler on Linux servers. Today, we'll switch gears from a simple tutorial to try to go more in depth about the kind of problems administrators tend to run into with cron. Debugging cron happens more often than most of us would like, and a lot of our time is spent just looking for what's wrong rather than actually fixing. Most of the mistakes are common, though, and I’ll try to go through a few of them along with debugging methods in this article.
MySQL has it`s own OS-independent users and security model, specifically involving the root account and its privileges. So, with this article, we will go over how to deal with the default root account and how to create new users with, and without, root privileges.
Right after the initial installation, you can connect to your MySQL server management shell only from localhost with mysql (not system) root login and, usually, without a password. So the first thing we should look at is how to set it (or, in the case that you set it earlier, reset it). If your root password is empty (usually happens after an automated installation) we`ll use the mysql-client shell to connect to and manage our server. With an empty password, you should use command 'mysql -u'. If you try to add the '-p' option, you will be forced to provide a password which can`t be empty with that flag.