Frequently Asked Questions

How can I contact the developers?

The best place to discuss PMM with developers and other community members is the community forum.

If you would like to report a bug, use the PMM project in JIRA.

What are the minimum system requirements for PMM?

PMM Server

Any system which can run Docker version 1.12.6 or later.

It needs roughly 1 GB of storage for each monitored database node with data retention set to one week.

Note

By default, retention is set to 30 days for Metrics Monitor and for Query Analytics. Also consider disabling table statistics, which can greatly decrease Prometheus database size.

Minimum memory is 2 GB for one monitored database node, but it is not linear when you add more nodes. For example, data from 20 nodes should be easily handled with 16 GB.

PMM Client

Any modern 64-bit Linux distribution. It is tested on the latest versions of Debian, Ubuntu, CentOS, and Red Hat Enterprise Linux.

Minimum 100 MB of storage is required for installing the PMM Client package. With good constant connection to PMM Server, additional storage is not required. However, the client needs to store any collected data that it is not able to send over immediately, so additional storage may be required if connection is unstable or throughput is too low.

How to control data retention for PMM?

By default, both Prometheus and QAN store time-series data for 30 days.

Depending on available disk space and your requirements, you may need to adjust data retention time.

You can control data retention by the following way.

  1. Select the PMM Settings dashboard in the main menu.

    _images/pmm-add-instance.png

    Choosing the PMM Settings menu entry

  2. In the Settings section, enter new data retention value in seconds.

    _images/pmm.settings_settings.png

    Entering data retention on the Settings dashboard

  3. Click the Apply changes button.

How often are nginx logs in PMM Server rotated?

PMM Server runs logrotate to rotate nginx logs on a daily basis and keep up to 10 latest log files.

Can I monitor multiple service instances?

Yes, you can add multiple instances of MySQL or some other service to be monitored from one PMM Client. In this case, you will need to provide a distinct port and socket for each instance, and specify a unique name for each instance (by default, it uses the name of the PMM Client host).

For example, if you are adding complete MySQL monitoring for two local MySQL servers, the commands could look similar to the following:

$ sudo pmm-admin add mysql --username root --password root instance-01 127.0.0.1:3001
$ sudo pmm-admin add mysql --username root --password root instance-02 127.0.0.1:3002

For more information, run

$ pmm-admin add mysql --help

Can I rename instances?

You can remove any monitoring instance as described in Removing monitoring services with pmm-admin remove and then add it back with a different name.

When you remove a monitoring service, previously collected data remains available in Grafana. However, the metrics are tied to the instance name. So if you add the same instance back with a different name, it will be considered a new instance with a new set of metrics. So if you are re-adding an instance and want to keep its previous data, add it with the same name.

Can I add an AWS RDS MySQL or Aurora MySQL instance from a non-default AWS partition?

By default the RDS discovery works with the default aws partition. But you can switch to special regions, like the GovCloud one, with the alternative AWS partitions (e.g. aws-us-gov) adding them to the Settings via the PMM Server API:

_images/aws-partitions-in-api.png

You can specify any of them instead of the aws default value, or use several of them, with the JSON Array syntax: ["aws", "aws-cn"].

How to troubleshoot communication issues between PMM Client and PMM Server?

Broken network connectivity may be caused by rather wide set of reasons. Particularly, when using Docker, the container is constrained by the host-level routing and firewall rules. For example, your hosting provider might have default iptables rules on their hosts that block communication between PMM Server and PMM Client, resulting in DOWN targets in Prometheus. If this happens, check firewall and routing settings on the Docker host.

Also PMM is able to generate a set of diagnostics data which can be examined and/or shared with Percona Support to solve an issue faster. You can get collected logs from PMM Client using the pmm-admin summary command. Obtaining logs from PMM Server can be done by specifying the ``https://<address-of-your-pmm-server>/logs.zip` URL, or by clicking the server logs link on the Prometheus dashboard:

_images/get-logs-from-prometheus-dashboard.png

What resolution is used for metrics?

MySQL metrics are collected with different resolutions (5 seconds, 5 seconds, and 60 seconds by default). Linux and MongoDB metrics are collected with 1 second resolution.

In case of bad network connectivity between PMM Server and PMM Client or between PMM Client and the database server it is monitoring, scraping every second may not be possible when latency is higher than 1 second.

You can change the minimum resolution for metrics by the following way:

  1. Select the PMM Settings dashboard in the main menu.

    _images/pmm-add-instance.png

    Choosing the PMM Settings menu entry

  2. In the Settings section, choose proper metrics resolution with the slider. The tooltip of the slider will show you actual resolution values.

    _images/pmm.settings_settings.png

    Choosing metrics resolution on the Settings dashboard

  3. Click the Apply changes button.

Note

Consider increasing minimum resolution when PMM Server and PMM Client are on different networks, or when Adding an Amazon RDS MySQL, Aurora MySQL, or Remote Instance.

Table Of Contents

Previous topic

Terminology Reference