Statistics file limit has been reached (4287252)

By default Syslog-ng Store Box (SSB) sends an e-mail alert like this with the subject "Notification received: SSB-SNMP-MIB::ssbStatisticsError".
(If e-mail alerts have been disabled no e-mail alert is received.)

DISMAN-EVENT-MIB::sysUpTimeInstance  101741680
SNMPv2-MIB::snmpTrapOID.0  SSB-SNMP-MIB::ssbStatisticsError
XCB-SNMP-MIB::description  Skipped 5 rrd updates due to limit, first skipped id is unknown

The data visualized on the dashboard is outdated.

The data visualized in reports is outdated.

The file number limit for the statistics files has been reached.

Resolution 1

• Navigate to Log → Options → Dashboard statistics page
• Increase number of statistics files to keep in the "Maximum number of statistics to process" field.        

Note: Calculate the space needed. One statistics file is approximately 170KiB.

Warning! Extreme increases in the number of statistics files may cause performance issues.

Mitigating solutions

There are various solution to mitigate the issue.

Consider, that all of these solutions affect the statistics used in reports and on dashboard.

Mitigating resolution 1 - Remove needless statistics

• Navigate to Log → Options → Dashboard statistics page

• Turn off Time-Based or Top/least statistics for unnecessary categories
  • It is a good start to disable "Message facilities" and "Message severities" as they aren't strictly used in log messages.
  • If you use PatternDB but not interested in statistics of it, you can disable all PatternDB related item. If PatternDB isn't used, the statistics aren't generated, therefore no action needed.

Mitigating resolution 2 - Reduce the cleanup of unchanged statistics

• Navigate to Log → Options → Dashboard statistics page
• Decrease Cleanup value
  Statistics unchanged (not present in syslog-ng statistics output anymore) for this number of days will be cleaned up from the system.

Mitigating resolution 3 - Increase statistics sampling interval

• Navigate to Log → Options → Dashboard statistics page
• Increase Sampling intervalA less frequent sampling interval results in less precise graphs.