Check index failuren – How to solve related issues

Opster Team

Feb-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many errors.

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This guide will help you check for common problems that cause the log ” Check index failuren ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index and shard.

Log Context

Log “check index [failure]n{}” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

             if (!status.clean) {
                if (state == IndexShardState.CLOSED) {
                    // ignore if closed....
                logger.warn("check index [failure]\n{}"; new String(os.bytes().toBytes(); Charsets.UTF_8));
                if ("fix".equalsIgnoreCase(checkIndexOnStartup)) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("fixing index; writing new segments file ...");


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