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Displaying posts with tag: cacti (reset)
Tips from the trenches for over-extended MySQL DBAs

This post is a follow-up to my November 19 webinar, “Tips from the Trenches: A Guide to Preventing Downtime for the Over-Extended DBA,” during which I described some of the most common reasons DBAs experience avoidable downtime. The session was aimed at the “over-stretched DBA,” identified as the MySQL DBA short of time or an engineer of another discipline without the depth of the MySQL system. The over-stretched DBA may be prone to making fundamental mistakes that cause downtime through poor response time, operations that cause blocking on important data or administrative mishaps through the lack of best practice monitoring and alerting. (You can download my slides and view the recorded webinar here.)

Monitor the things
One of the aides to keeping the system up and …

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Galera data on Percona Cloud Tools (and other MySQL monitoring tools)

I was talking with a Percona Support customer earlier this week who was looking for Galera data on Percona Cloud Tools. (Percona Cloud Tools, now in free beta, is a hosted service providing access to query performance insights for all MySQL uses.)

The customer mentioned they were already keeping track of some Galera stats on Cacti, and given they were inclined to use Percona Cloud Tools more and more, they wanted to know if it was already supporting Percona XtraDB Cluster. My answer was: “No, not yet: you can install agents in each node (the regular way in the first node, then …

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Galera data on Percona Cloud Tools (and other MySQL monitoring tools)

I was talking with a Percona Support customer earlier this week who was looking for Galera data on Percona Cloud Tools. (Percona Cloud Tools, now in free beta, is a hosted service providing access to query performance insights for all MySQL uses.)

The customer mentioned they were already keeping track of some Galera stats on Cacti, and given they were inclined to use Percona Cloud Tools more and more, they wanted to know if it was already supporting Percona XtraDB Cluster. My answer was: “No, not yet: you can install agents in each node (the regular way in the first node, then …

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MySQL Monitoring With Cacti Using Percona Monitoring Plugins (1-minute resolution)

Today, just like many times before, I needed to configure a monitoring server for MySQL using Cacti and awesome Percona Monitoring Templates. The only difference was that this time I wanted to get it to run with 1 min resolution (using ganglia and graphite, both with 10 sec resolution, for all the rest of our monitoring in Swiftype really spoiled me!). And that’s where the usual pain in the ass Cacti configuration gets really amplified by the million things you need to change to make it work. So, this is a short checklist post for those who need to configure a Cacti server with 1 minute resolution and setup Percona Monitoring Plugins on it.

Configuring Cacti for 60-seconds polling

First of all, we need to take a Cacti server, which by default is configured to do polling …

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Percona Monitoring Plugins fix: Query Response Time

After switching from the Better Cacti Templates to the Percona Monitoring Plugins we suffered from the Query Response Time and the Query Time Histogram not graphing at all.

It took me a while to figure out why our new instance wasn’t graphing: the response time query was performing and the script was picking up its values. Also the rrd files were created but for some bizarre reason all values were set to “NaN”, in rrd/cacti terms: Not a Number. If you search on that subject you will come across a lot of (forum) postings stating you need to change your graph type to “GAUGE” or change the MIN/MAX values for your data templates. Strange as this was already set to a minimum of 0 and a maximum of an unsigned 64 bit integer.

After running the …

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Unindexed queries can be really expensive

The story happened with a webshop application running on Amazon EC2 microinstances. Actually on two instance. Amazon business model is basically simple, they ask money for only three things: Cpu time, IOPS and network traffic. Everybody (including me) thinks for the first time network traffic will be the bottleneck until they got the first bill (it can be even after one year considering the free tier). Actually in this category the IOPS is the most expensive.

Symptoms

On the cacti diagrams I saw strange datas. The created temp tables on disk and created temp files were much higher than created temp tables. The 67% of temporary tables were created on disk. This is very far from optimal.

Temporary objects in MySQL

Quick patch

II increased the max_heap_table_size and tmp_table_size from …

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Vote for MySQL[plus] awards 2011 !

First of all, I wish you a happy new year.
Many things happened last year, it was really exciting to be involved in the MySQL ecosystem.
I hope this enthusiasm will be increased this year, up to you !

To start the year, I propose the MySQL[plus] Awards 2011
It will only take 5 minutes to fill out these polls.
Answer with your heart first and then with your experience with some of these tools or services.

Polls will be closed January 31, so, vote now !
For “other” answers, please,  let me a comment with details.

Don’t hesitate to submit proposal for tools or services in the comments.
And, please, share these polls !

 

Note: There is a poll embedded within this post, …

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Version 1.1.8 of Better Cacti Templates released

I’ve released version 1.1.8 of the Better Cacti Templates project. This release includes a bunch of bug fixes and several important new graphs. There are graphs for the new response-time statistics exposed in Percona Server, and a new set of graphs for MongoDB.

There are upgrade instructions on the project wiki for this and all releases. There is also a comprehensive tutorial on …

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Careful how you monitor MySQL

I was recently struck by a problem which is unusual. In order to keep an eye on the database server I use nagios, cacti, merlin and some local scripts to monitor the database instance and ensure that it is working properly.  That normally works fine.  The different monitor processes do various things, one of which is to monitor the replication status of a slave, and warn me if the replication is not working or if it’s behind. This is done with the command SHOW SLAVE STATUS.

The server I was looking at runs some large local batch jobs aggregating data. Unfortunately, I was experiencing that replication was interfering with these batch jobs so decided to see if things would perform better if I stopped replication and let the batch …

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Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 41 bytes) in /usr/share/cacti/site/lib/xml.php on line 32

I was trying to setup cacti on my ubuntu desktop to gather metrics from few new database servers we were planning to replace. Installed cacti using the following command

apt-get install cacti

Then the next step was to download and the install the cacti mysql templates from http://code.google.com/p/mysql-cacti-templates/. Thanks to Baron, was able to get this up and running fast using the templates. But had one problem though, while importing the mysql template “cacti_host_template_x_mysql_server_ht_0.8.6i-sver1.1.7.xml” cacti bombed with the below error

Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 41 bytes) in /usr/share/cacti/site/lib/xml.php on line 32

The fix was to edit “/etc/php5/apache2/php.ini” change the parameter “memory_limit” from 16M to 32M and …

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