[FORBIDDEN/12/index read-only / allow delete errors
When you see these types of errors in your log-files then elastic has switched to read-only mode. This will cause that the catalogue can no longer be updated. Elastic will switch to read-only mode when the available disk-space is less then 5%. Note that elastic will stay in read-only mode even when you make more disk space available.
First thing to do when you see these types of errors is to configure elastic so that it doesn't switch quickly to read-only mode.
This can be done by manually configuring the thresholds in the elasticsearch.yml. This file can be found the config folder of elastic.
cluster.routing.allocation.disk.watermark.low: "20gb"
cluster.routing.allocation.disk.watermark.high: "15gb"
cluster.routing.allocation.disk.watermark.flood_stage: "10gb"
Note that the mentioned thresholds above should be configured in such a way that cluster.routing.allocation.disk.watermark.low is higher than cluster.routing.allocation.disk.watermark.high and that cluster.routing.allocation.disk.watermark.high should be higher than cluster.routing.allocation.disk.watermark.flood_stage.
The config above will ensure that elastic only switches to read-only mode when there is less then 10gb available.
Elastic search
The catalogue of the archive is hosted by elastic. Since the 201802 release elastic is no longer embedded in the Archive web gui but running as a seperate process.
Elastic is usually installed as in seperate folder in the