KB-1766 "High disk watermark [90%] exceeded" warning seen in the search-server logs

Symptoms

Warnings of the following type are observed in the <APPIAN_HOME>\logs\search-server\search-server.log:

[WARN ][org.elasticsearch.cluster.routing.allocation.DiskThresholdMonitor] [Node <HOSTNAME>:<SEARCH_SERVER_PORT>] high disk watermark [90%] exceeded on [<HOSTNAME>][Node <HOSTNAME>:<SEARCH_SERVER_PORT>][<APPIAN_HOME>/search-server/data/nodes/0] free: X.Xgb[X.X%],, shards will be relocated away from this node

If the following warning is seen in the <APPIAN_HOME>\logs\search-server\search-server.log, see KB-1763 in addition to this article:

[WARN ][org.elasticsearch.cluster.routing.allocation.DiskThresholdMonitor] [Node <HOSTNAME>:<SEARCH_SERVER_PORT>] flood stage disk watermark [95%] exceeded on [<HOSTNAME>][Node <HOSTNAME>:<SEARCH_SERVER_PORT>][<APPIAN_HOME>/search-server/data/nodes/0] free: X.Xgb[X.X%], all indices on this node will be marked read-only

Cause

This warning is seen when the disk usage crosses 90% of the available space on the server which hosts the search server.

Action

Reduce disk space on the server. KB-1255 provides guidance on how to address high disk usage of certain Appian components. If disk space cannot be reduced, add disk space. If the warning messages persist after disk has been reduced to a value below 90%, clear the search server indices. See the Action section of KB-1082 for steps on how to clear the search server indices.

The hardware requirements documented here provide general guidelines regarding the necessary hardware allotment for an Appian environment.

Affected Versions