Description

In Junos OS, it is possible to experience an inability to commit changes even though no user has issued the command > configure exclusive . This could be caused by a limitation in the juniper.db file size.

Symptoms

Changes to the configuration fail to commit, even though no user has issued the command > configure exclusive .  This usually happens when the proposed configuration changes cause juniper.db to exceed the size limit. There is a limitation in Junos OS, where if the juniper.db file in /var/run/db exceeds 700Mb, it could lead to commit locks.

Solution

Commit fails with the message:

configuration database size limit exceeded.
 

A log message similar to the following may be seen:

Oct 20 02:57:06 routername mgd[38862]: UI_DBASE_EXTEND_FAILED: Unable to extend configuration database file '/var/run/db/juniper.db' to size 0xf000000: size exceeds limit
 

This is a known limitation and is not a bug. The solution is to watch the juniper.db file and ensure that the configuration does not have too many lines in it.
 

As a workaround, it is recommended to simplify the configuration using groups with wildcards or less specific match polices in a firewall filter. In addition, the dynamic-db can be used.

Reinitializing the mgd process can help to mitigate this issue as it significantly reduces the size of the configuration database.

Command to reinitialize the mgd:
> mgd -I
 

Before re-initializing the mgd:

root@device> show system configuration database usage

Maximum size of the database: 665.99 MB

Current database size on disk: 665.50 MB <<<<<<<

Actual database usage: 665.16 MB

Available database space: 0.84 MB

 

After re-initializing the mgd:

root@device> show system configuration database usage

Maximum size of the database: 665.99 MB

Current database size on disk: 2.50 MB <<<<<<<

Actual database usage: 2.46 MB

Available database space: 663.53 MB

Please open a case with Juniper Technical support  JTAC Support  for further investigation.

Modification History

2020-06-12: Article verified for accuracy. No changes required.
2023-08-29: Article updated with the new workaround i.e to reinitialize the mgd.

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