The Percona Monitoring Plugins (PMP) provide some free tools to make it easier to monitor PXC/Galera nodes. Monitoring broadly falls into two categories: alerting and historical graphing, and the plugins support Nagios and Cacti, respectively, for those purposes.
Graphing
An update to the PMP this summer (thanks to our Remote DBA team for supporting this!) added a Galera-specific host template that includes a variety of Galera-related stats, including:
The technologies allowing to build highly-available (HA) MySQL solutions are in constant evolution and they cover very different needs and use cases. In order to help people choose the best HA solution for their needs, we decided, Jay Janssen and I, to publish, on a regular basis (hopefully, this is the first), an update on the most common technologies and their state, with a focus on what type of workloads suite them best. We restricted ourselves to the open source solutions that provide automatic failover. Of course, don’t simply look at the number of Positives/Negatives items, they don’t have the same values. Should you pick any of these technologies, heavy testing is mandatory, HA is never beyond scenario that have been tested.
Percona XtraDB Cluster (PXC)
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[Read more]Checking throughput with async MySQL replication
Replication throughput is the measure of just how fast the slaves can apply replication (at least by my definition). In MySQL async replication this is important to know because the single-threaded apply nature of async replication can be a write performance bottleneck. In a production system, we can tell how fast the slave is currently running (applying writes), and we might have historical data to check for the most throughput ever seen, but that doesn’t give us a solid way of determining where we stand right NOW().
An old consulting trick to answer this question is to simply stop replicating on your slave for a minute, (usually just the SQL_THREAD), restart it and watch how long it takes to catch up. We can also watch the slave thread apply rate during this interval to get a sense of just how many writes per second we can do and compare that with the normal rate …
[Read more]Percona XtraDB Cluster (PXC) itself manages quorum and node failure. Minorities of nodes in a network partition situation will move themselves into a Non-primary state and not allow any DB activity. Nodes in such a state will be easily detectable via SHOW GLOBAL STATUS variables.
It’s common to use HAproxy with PXC for load balancing purposes, but what if you are planning to just send …
[Read more]I occasionally see customers who are taking backups from their PXC clusters that complain that the cluster “stalls” during the backup. As I wrote about in a previous blog post, often these stalls are really just Flow Control. But why would a backup cause Flow control?
Most backups I know of (even Percona XtraBackup) take a FLUSH TABLES WITH READ LOCK (FTWRL) at some point in the backup process. This can be disabled in XtraBackup (in certain circumstances), but it is enabled by default.
If you go to your active cluster right now an execute a …
[Read more]Percona XtraDB Cluster (PXC) is different enough from async replication that it can be a bit of a puzzle how to do things the Galera way. This post will attempt to illustrate the basics of setting up 2 node PXC cluster from scratch.
Requirements
Two servers (could be VMs) that can talk to each other. I’m using CentOS for this post. Here’s a dirt-simple Vagrant setup: https://github.com/jayjanssen/two_centos_nodes to make this easy (on Virtualbox).
These servers are talking over the 192.168.70.0/24 internal network for our example.
jayj@~/Src $ git clone https://github.com/jayjanssen/two_centos_nodes.git jayj@~/Src $ cd two_centos_nodes jayj@~/Src/two_centos_nodes $ vagrant up Bringing machine 'node1' up …[Read more]
I will be in Prato (Firenze), Italy Thursday and Friday (September 19th and 20th) to deliver 2 presentations at OSS4B:
If you want to learn about these projects or discuss anything related to MySQL and Percona, join the conference and don’t hesitate to come to talk to me. I will be very happy to answer your questions.
I also want to share a list of tracks I would like to attend (there is also another one but it’s at the same time as mine so I won’t tell it )
…[Read more]One type of question we get very often (even in the form of filed bugs!) is how to switch from stock MySQL to Percona Server or switch from Percona Server 5.5 to Percona XtraDB Cluster using yum, but à la apt-get, i.e. having yum handle the replace.
In its simplest form, yum cannot replace a package¹ for another like apt-get does:
# yum -q -q install
Percona-XtraDB-Cluster-server
Error: Percona-XtraDB-Cluster-server conflicts with
Percona-Server-server-55
Error: Percona-XtraDB-Cluster-client conflicts with
Percona-Server-client-55
Error: Percona-XtraDB-Cluster-shared conflicts with
Percona-Server-shared-55
One solution for this is to manually uninstall …
[Read more]Good news everyone! I recently presented a webinar: Percona Server 5.6: Enterprise Grade MySQL. It was also recorded so you can watch along or view the slide deck. As with all my talks, I am not simply reading the slides so it really is worth to listen to the audio rather than just glance through the slide deck.
There were a number of great questions asked which I’ll answer below:
Q: How does Stewart feel about this version of 5.6 taking into consideration “Stewart’s .20 rule?” (ref 2013 Percona Live Conference).
A: For those who aren’t familiar with it, I have a rule which I call “Stewart’s dot twenty rule” which I’ve posted a few times about on my personal blog. It …
[Read more]Failure is an unavoidable part of IT life, but it does not always have to imply MySQL service downtime. In the years I have been working at Percona, I have been involved in many customer emergency cases, and I have seen a good number of problems that could have been avoided or alleviated if relatively simple proactive measures were taken.
On July 17th 2013, at 10 a.m. PDT, I will be delivering a webinar focused on presenting the Top 5 such measures, with the objective of helping you assess your current situation, and implement any needed changes to avoid production downtime in the future. The webinar is titled: “5 Proactive Measures to Minimize MySQL Downtime.”
Later that day, I will be delivering the …
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