I talk with lot of people who are really interested in Percona XtraDB Cluster (PXC) and mostly they are interested in PXC as a high-availability solution. But, what they tend not to think too much about is if moving from async to synchronous replication is right for their application or not. Facts about Galera replication [...]
Follow these basics when migrating to Percona XtraDB Cluster for MySQL
May 1, 2013 By 10 Comments
Galera/Percona XtraDB Cluster (PXC) for MySQL is a hot thing right now and some users jump right in without enough testing. Consequently, they’re more likely to either suffer failure or issues that prevent them from moving forward. If you are thinking of migrating your workload to Percona XtraDB Cluster, make sure to go through these [...]
Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL now available
April 17, 2013 By 2 Comments
Percona is glad to announce the release of Percona XtraDB Cluster 5.5.30-23.7.4 for MySQL on April 17, 2013. Binaries are available from the downloads area or from our software repositories. New Features: Percona XtraDB Cluster has implemented initial implementation of weighted quorum. Weight for node can be assigned via pc.weight option in the wsrep_provider_options variable. [...]
Investigating MySQL Replication Latency in Percona XtraDB Cluster
March 3, 2013 By 13 Comments
I was curious to check how Percona XtraDB Cluster behaves when it comes to MySQL replication latency — or better yet, call it data propagation latency. It was interesting to see whenever I can get stale data reads from other cluster nodes after write performed to some specific node. To test it I wrote quite a [...]
Replication checksums in MySQL 5.6
February 15, 2013 By 3 Comments
MySQL 5.6 has an impressive list of improvements. Among them, replication checksums caught my attention as it seems that many people misunderstand the real added value of this new feature. I heard people think that with replication checksums, data integrity between the master and its replicas is now enforced. As we’ll see, it’s not that [...]
Percona XtraDB Cluster (PXC): what about GRA_*.log files ?
December 19, 2012 By Leave a Comment
How easy is it to identify and debug Percona XtraDB Cluster replication problem ? If you are using PXC, you may have already seen in your datadirectory several log files starting with GRA_ Those files correspond to a replication failure. That means the slave thread was not able to apply one transaction. For each of [...]
Understanding Multi-node writing conflict metrics in Percona XtraDB Cluster and Galera
November 20, 2012 By 17 Comments
I have addressed previously how multi-node writing causes unexpected deadlocks in PXC, at least, it is unexpected unless you know how Galera replication works. This is a complicated topic and I personally feel like I’m only just starting to wrap my head around it. The magic of Galera replication The short of it is that Galera [...]
Percona XtraDB Cluster – installation and setup webinar follow up Q&A
October 28, 2012 By 4 Comments
Thanks for all, who attended my webinar, I got many questions and I wanted to take this opportunity to answer them. Q: Even ntp has a delay of 0.3-0.4 between servers does that mean a 0.25 as from logs can be an issue ? A: My demo vms were running for a few hours before [...]
Automation: A case for synchronous replication
September 19, 2012 By 2 Comments
Just yesterday I wrote about math of automatic failover today I’ll share my thoughts about what makes MySQL failover different from many other components and why asynchronous nature of standard replication solution is causing problems with it. Lets first think about properties of simple components we fail over – web servers, application servers etc. We [...]
Percona XtraDB Cluster: Failure Scenarios with only 2 nodes
July 25, 2012 By 6 Comments
During the design period of a new cluster, it is always advised to have at least 3 nodes (this is the case with PXC but it’s also the same with PRM). But why and what are the risks ? The goal of having more than 2 nodes, in fact an odd number is recommended in [...]
