Hard Out Of Memory Error with free memory

Today i got an email with the following message:
Hard Out Of Memory Error. Bucket “EventLog” on node XXX.XXX.XXX.XXX is full. All memory allocated to this bucket is used for metadata.

The bucket had 6Gb of ram at the time of the error. After the error i set the ram to 12Gb.
But according to the picture i only have 80 MB of metadata. So i believe that even with 6GB it shouldn’t show that error
I’m not using Full Eviction.

What am i missing?
Why this error?

Which version of Couchbase Server are you running?

Additionally were you running a backup around the time that this error message appeared?

I’m running Couchbase Server 4.0 Community Edition.
I was not running a backup and the Auto-Compaction was not running also.

I can see there’s something odd going on with your cluster as the replica + active user data total should only be ~100MB but the UI is reporting it as 5.32GB, from the screenshots I am not able to see what is taking up the memory though.

Additionally your resident ratio is exceptionally low, indicating that something has caused your documents to get ejected from memory.

I have 461528 documents on bucket and the 5.32Gb i believe is the correct value, if you see in the image total disk size is 3.09Gb.
the replica + active its wrong. I don’t know what could cause this. Or the ejection.
Any ideas how to get back to normal values?
If you need more printscreens or other information, let me know.

Restarting couchbase restore values to normal.
But now the bucket is using all the ram, and when i try to decrease the ram to old value, it says its in use.
It’s possible to force ejection of the data to low the data ram usage?