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# 4 Real-time export of events, item values, trends

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#### Overview

It is possible to configure real-time exporting of trigger events, item
values and trends in a newline-delimited JSON format.

Exporting is done into files, where each line of the export file is a
JSON object. Value mappings are not applied.

In case of a write error (data cannot be written to the export file or
the export file cannot be renamed or a new one cannot be created after
renaming it), the data item is dropped and never written to the export
file. It is written only in the Zabbix database. Writing data to the
export file is resumed when the writing problem is resolved.

Note that ***before Zabbix 4.0.16***, in case of a write error, Zabbix
would retry with a 10 second interval until success. This behavior,
while ensuring history data equivalence between database and export
files resulted in actually stopping monitoring until the problem with
the export file was fixed. Since 4.0.16 the priority is given to
continued monitoring rather than keeping the export file in sync with
database at all cost.

For precise details on what information is exported, see the [export
protocol](/manual/appendix/protocols/real_time_export) page.

Note that host/item can have no metadata (host groups, host name, item
name) if the host/item was removed after the data was received, but
before server exported data.

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#### Configuration

Real-time export of trigger events, item values and trends is configured
by specifying a directory for the export files - see the `ExportDir`
parameter in server
[configuration](/manual/appendix/config/zabbix_server).

Another parameter - `ExportFileSize` may be used to set the maximum
allowed size of an individual export file. When a process needs to write
to a file it checks the size of the file first. If it exceeds the
configured size limit, the file is renamed by appending .old to its name
and a new file with the original name is created.

::: noteimportant
A file will be created per each process that will
write data (i.e. approximately 4-30 files). As the default size per
export file is 1G, keeping large export files may drain the disk space
fast.
:::

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