Skip to content

Commit

Permalink
Update docs on increasing the persistent log sizes
Browse files Browse the repository at this point in the history
Signed-off-by: Leandro Motta Barros <[email protected]>
Change-type: patch
  • Loading branch information
lmbarros committed Apr 26, 2022
1 parent f69923b commit 162abe4
Showing 1 changed file with 4 additions and 2 deletions.
6 changes: 4 additions & 2 deletions pages/learn/manage/device-logs.md
Original file line number Diff line number Diff line change
Expand Up @@ -20,12 +20,14 @@ The ability to read logs from the different system services running in balenaOS

Persistent logging can be enabled using the Configuration tab on the sidebar for either a specific device or fleet wide. Select 'Activate' to enable persistent logging on your device/fleet. The device(s) will reboot once persistent logging is activated to ensure that the settings are applied. Once enabled, the logs are stored in `/var/log/journal/<uuid>` where the UUID is the device UUID.

Depending on the OS version, the size of persistent logs can also be increased to store more logs than the default size (32 MB currently). Do keep in mind persistent logging increases the wear on the storage medium due to increased writes. Refer to [long term storage of device logs](#long-term-device-logs-storage) for ways to offset this.
If you are running in [development mode][devvprod], and depending on the OS version, the size of persistent logs can also be increased to store more logs than the default size (32 MB currently). This can be done by adjusting the `SystemMaxUse=` setting in `/etc/systemd/journald.conf.d/journald-balena-os.conf` (refer to [journald.conf docs](https://www.freedesktop.org/software/systemd/man/journald.conf.html) for more information).

The `RuntimeMaxUse=` in `/etc/systemd/journald.conf` can be increased in order to potentially increase the amount of logs that can be stored. Refer to [journald.conf docs](https://www.freedesktop.org/software/systemd/man/journald.conf.html) for more information regaridng the same.
Do keep in mind persistent logging increases the wear on the storage medium due to increased writes. Refer to [long term storage of device logs](#long-term-device-logs-storage) for ways to offset this.

## Long term device logs storage

If you are dealing with excessive logs, then persistent logging might not be a reliable long term solution. Persistent logging results in increased writes on the storage media of the device which leads to your storage media degrading over time.

Instead, device logs can be streamed using the supervisor API. Refer to the [Supervisor's journald](https://www.balena.io/docs/reference/supervisor/supervisor-api/#journald-logs) endpoint. Through this endpoint, device logs can be streamed to whichever cloud monitoring platform you use to store logs reliably over the course of time. For example using a solution like [Datadog](https://www.balena.io/blog/iot-fleet-monitoring-with-datadog-and-balenacloud-how-small-agent-containers-make-a-big-impact/).

[devvprod]:/reference/OS/overview/2.x/#development-vs-production-mode

0 comments on commit 162abe4

Please sign in to comment.