Buffering / Storage
The end-goal of Fluent Bit is to collect, parse, filter and ship logs to a central place. In this workflow there are many phases and one of the critical pieces is the ability to do buffering : a mechanism to place processed data into a temporal location until is ready to be shipped.
By default when Fluent Bit process data, it uses Memory as a primary and temporal place to store the record logs, but there are certain scenarios where would be ideal to have a persistent buffering mechanism based in the filesystem to provide aggregation and data safety capabilities.
Starting with Fluent Bit v1.0, we introduced a new storage layer that can either work in memory or in the file system. Input plugins can be configured to use one or the other upon demand at start time.
The storage layer configuration takes place in two areas:
- Service Section
- Input Section
The known Service section configure a global environment for the storage layer, and then in the Input sections defines which mechanism to use.
a Service section will look like this:
that configuration configure an optional buffering mechanism where it root for data is /var/log/flb-storage/, it will use normal synchronization mode, without checksum and up to a maximum of 5MB of memory when processing backlog data.
Optionally, any Input plugin can configure their storage preference, the following table describe the options available:
The following example configure a service that offers filesystem buffering capabilities and two Input plugins being the first based in memory and the second with the filesystem: