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Displaying posts with tag: Percona MySQL Consulting (reset)
The cost of not properly managing your databases

Every day hundreds of millions of dollars are wasted by allowing improperly tuned or misconfigured systems, misunderstood infrastructure, and inefficient IT operations to live and thrive in data centers around the globe. There are both direct and indirect costs associated with allowing these unhealthy systems to continue to exist. Let’s look at some.

The setup:

Let us start by using a small example. We will start by looking at a small database setup. This setup will have a single master-slave, with a database size of lets say 500GB. Traffic is steady and let’s say this translates into 500 IOPS on the master. You have chosen to host this on Amazon’s AWS. A common way of ensuring backups occur in AWS is to setup ebs snapshots of the slave. In terms of usage, let us assume your CPU is about 50% used and you have about 20GB of hot data that needs to stay in the memory for the database.

If we look at what this …

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Is MySQL’s innodb_file_per_table slowing you down?

MySQL’s innodb_file_per_table is a wonderful thing – most of the time. Having every table use its own .ibd file allows you to easily reclaim space when dropping or truncating tables. But in some use cases, it may cause significant performance issues.

Many of you in the audience are responsible for running automated tests on your codebase before deploying to production. If you are, then one of your goals is having tests run as quickly as possible so you can run them as frequently as possible. Often times you can change specific settings in your test environment that don’t affect the outcome of the test, but do improve throughput. This post discusses how innodb_file_per_table is one of those settings.

I recently spoke with a customer whose use case involved creating hundreds of tables on up to 16 schemas …

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MySQL ring replication: Why it is a bad option

I’ve recently worked with customers using replication rings with 4+ servers; several servers accepting writes. The idea behind this design is always the same: by having multiple servers, you get high availability and by having multiple writer nodes, you get write scalability. Alas, this is simply not true. Here is why.

High Availability

Having several servers is a necessary condition to have high availability, but it’s far from sufficient. What happens if for instance C suddenly disappears?

  • The replication ring is broken, so updates from A and B will never go to D. D will then quickly become so out-of-date that it’s not going to be usable. But wait! A will no longer receive the updates from B so A …
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OpenStack users shed light on Percona XtraDB Cluster deadlock issues

I was fortunate to attend an Ops discussion about databases at the OpenStack Summit Atlanta this past May as one of the panelists. The discussion was about deadlock issues OpenStack operators see with Percona XtraDB Cluster (of course this is applicable to any Galera-based solution). I asked to describe what they are seeing, and as it turned out, nova and neutron uses the SELECT … FOR UPDATE SQL construct quite heavily. This is a topic I thought was worth writing about.

Write set replication in a nutshell (with oversimplification)

Any node is writable, and replication happens in write sets. A write …

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Using MySQL 5.6 Global Transaction IDs (GTIDs) in production: Q&A

Thank you to all of you who attended my webinar last week about Global Transaction IDs (GTIDs), which were introduced in MySQL 5.6 to make the reconfiguration of replication straightforward. If you missed my webinar, you can still listen to the recording and download the sides (free). We had a lot of questions during the webinar, so let me try to answer them here. Please let me know in the comments if additional clarification is needed.

Q: Does GTID provide any benefit to master-master replication? If yes, how?
Q: Is ACTIVE ACTIVE MASTER MASTER successful in MySQL with GTID?

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Migrating to Percona XtraDB Cluster 2014 edition: Sept. 10 MySQL webinar

Join me online next week (September 10 at 10 a.m. PDT) for my live webinar on Migrating to Percona XtraDB Cluster.  This was a popular webinar that I gave a few years ago, so I’m doing it again with updates for Percona XtraDB Cluster 5.6 (PXC) and all the latest in the Galera world.

This webinar will be really good for people interested in getting an overview of what PXC/Galera is, what it would take to adopt it for your application, and some of the differences and challenges it brings compared with a conventional MySQL Master/slave setup.  I’d highly suggest attending if you are considering Galera in your environment …

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Using sysbench 0.5 for performing MySQL benchmarks

Given the recent excitement & interest around OpenStack I wanted to make sure I was ready to conduct appropriate evaluations of system performance.  I generally turn to sysbench since it comes with a variety of different tests (accessed via –test= option interface), including:

  • fileio – File I/O test
  • cpu – CPU performance test
  • memory – Memory functions speed test
  • threads – Threads subsystem performance test
  • mutex – Mutex performance test

As you can see, sysbench lets you stress many of the fundamental components of your hardware and infrastructure, such as your disk subsystem, along with your CPUs and memory. An additional option exists that is designed to perform synthetic stress testing of MySQL, and I was surprised when I didn’t see it in the above list on version 0.5, as it used to show up as “oltp – OLTP test”. What happened to …

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How to use MySQL Global Transaction IDs (GTIDs) in production

Reconfiguring replication has always been a challenge with MySQL. Each time the replication topology has to be changed, the process is tedious and error-prone because finding the correct binlog position is not straightforward at all. Global Transaction IDs (GTIDs) introduced in MySQL 5.6 aim at solving this annoying issue.

The idea is quite simple: each transaction is associated with a unique identifier shared by all servers in a given replication topology. Now reconfiguring replication is easy as the correct binlog position can be automatically calculated by the server.

Awesome? Yes it is! However GTIDs are also changing a lot of things in how we can perform operations on replication. For instance, skipping transactions is a bit more difficult. Or you can get bitten by …

[Read more]
How to use MySQL Global Transaction IDs (GTIDs) in production

Reconfiguring replication has always been a challenge with MySQL. Each time the replication topology has to be changed, the process is tedious and error-prone because finding the correct binlog position is not straightforward at all. Global Transaction IDs (GTIDs) introduced in MySQL 5.6 aim at solving this annoying issue.

The idea is quite simple: each transaction is associated with a unique identifier shared by all servers in a given replication topology. Now reconfiguring replication is easy as the correct binlog position can be automatically calculated by the server.

Awesome? Yes it is! However GTIDs are also changing a lot of things in how we can perform operations on replication. For instance, skipping transactions is a bit more difficult. Or you can get bitten by …

[Read more]
Measuring failover time for ScaleArc load balancer

ScaleArc hired Percona to benchmark failover times for the ScaleArc database traffic management software in different scenarios. We tested failover times for various clustered setups, where ScaleArc itself was the load balancer for the cluster. These tests complement other performance tests on the ScaleArc software – sysbench testing for latency and testing for WordPress acceleration.

We tested failover times for Percona XtraDB Cluster (PXC) and MHA (any traditional MySQL replication-based solution works pretty much the same way).

In each case, we tested failover with a rate limited …

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