One of the more common questions I get asked is which Linux distribution I would use for a MySQL database server. Bearing the responsibility for someone else’s success means I should advise something that is stable, reliable, easy to manage and has plenty of resources available online. It should also allow running MySQL without too much hassle. Unless there are individual circumstances, it actually makes the decision quite easy.
There are probably only a few distributions, which can be considered: CentOS, Debian, RedHat Enterprise Linux, SuSE Linux and Ubuntu. Of course CentOS and Ubuntu derive from RedHat and Debian respectively, but their install bases are large enough to mention them separately. Running MySQL won’t be much different whether one or another distribution is used. All use common Linux kernel – the heart of Linux operating system – which in principle will behave the same way in all cases. The kernel versions may be different in different distributions as for example RedHat is very conservative in that area for the sake of compatibility with drivers and applications throughout a release lifetime, which can be even several years. Newer kernel versions may carry new features or slight performance improvements, however these days it is rarely important to MySQL users. If it is to you, then you probably did your own research and benchmarks already and this post is not for you.
For most people, managing a database server during its lifetime comes down to this rather boring process – install, configure, tune, start/stop MYSQL, upgrade MySQL, 10x start/stop MySQL, upgrade MySQL, downgrade MySQL, upgrade MySQL, install a security fix for something, 20x start/stop MySQL, upgrade MySQL, … . Restarting and changing MySQL version might just be the most critical operations you ever do once server is moved into production. Success and efficiency of these operations may directly impact service availability, which means that what you could wish for the most are quick and problem free restarts and upgrades (or downgrades).
From my experience, and I have done thousands upgrades and downgrades in my life, the least number of problems come from RPM packages available in RedHat, CentOS and SuSE. In fact, I cannot recall encountering any serious problem with that package management system. Moreover, I have not seen broken systems, where installing or updating a RPM package would be impossible without resolving tons of problems first. It can obviously mean that RPM has flaws and does not verify consistency very carefully, but it never turned out to be any problem.
On the other end there are Debian and Ubuntu. Both use tool called dpkg for package management. There isn’t a month that I log in to a system based on either distribution where there are no issues with packages consistency. Unfinished installations, unresolved conflicts are so common that it’s just beyond simple negligence. The packaging system is just not robust enough. Another problem is that one broken package may block you from installing or uninstalling anything else. Imagine that someone left system in such shape, you prepared for downtime, stopped MySQL and… error – text editor has not been properly installed, so you cannot upgrade MySQL either until the problem is fixed. In a stressful situation when downtime clock ticks – annoying at best. Resolving problems can easily lead to unexpected consequences. Here’s a different scenario:
# apt-get install binutils
E: dpkg was interrupted, you must manually run 'dpkg --configure -a' to correct the problem.
While everyone should stop and check what this means instead of following the advice blindly, many still would just do as they were instructed. In this particular case the problems were with MySQL packages upgraded from 5.1 to 5.5. The former were not fully uninstalled, the latter were in half-configured state. Obviously binutils has nothing to do with MySQL, but it would not install anyway. The larger problem – chances are that fixing this with ‘dpkg –configure -a’ would cause MySQL to shut down. The MySQL package scripts for Debian force MySQL stop/start upon completion and unlike RPM, dpkg does not have any opt-out option.
More problems can come from the standard Debian init (startup) script for MySQL. By default it not only starts database, but also updates system tables (if needed), scans all tables for consistency problems, etc. I mean, that works great for a computer at home or a tiny and unimportant system, but any of these operations may have severe consequences on a large production system. This is why all of this extra functionality was stripped from Percona Server. This behavior actually appears to be a general problem with Debian – it wants to be smarter than you. This might work for desktops, but anywhere else it is plain stupid and makes you waste time on outsmarting a wise-ass system. Of course I do know some people who like such approach, but he is Belgian and they were unable to form a government for 541 days… (congrats that you finally made it this week, btw! Image may be NSFW.
Clik here to view.
)
The init scripts for RedHat, CentOS and SuSE are simple and do only what’s required of them – stop or start MySQL. No problems there.
It’s now clear that I never recommend Debian or Ubuntu, because I do not like some of the “mechanics” and I feel people are generally safer if they do not use any of these two. With the choice left between RedHat/CentOS and SuSE, I lean towards the former. Why? RedHat and CentOS are the only platforms getting packages from all MySQL and MySQL-fork vendors – Oracle, MariaDB and Percona. By my observations RedHat and CentOS are also much more frequently used with MySQL, so there will be more resources available online.
But if you are a skilled systems administrator or your company hires one, then you could use pretty much anything, including my favorites such as Slackware and Gentoo.
In the beginning I mentioned that individual circumstances may influence the decision. One example of such specific case, which limits your options, is for example a requirement for commercial support for the operating system. You will have to choose between RedHat or SuSE. Another such case can be related to hardware. Any newly released component may simply lack support from the Linux kernel, but this can also be the case for any high-end/enterprise class equipment. Hardware vendors may release Linux drivers on their own, but often only for very specific Linux distributions.
The post Which Linux distribution for a MySQL database server? A specific point of view. appeared first on MySQL Performance Blog.