Creating an index Nest

Creating an index in older versions

There are two main ways that you can accomplish this as outlined in the Nest Create Index Documentation:

Here is the way where you directly declare the index settings as Fluent Dictionary entries. Just like you are doing in your example above. I tested this locally and it produces the index settings that match your JSON above.

        var response = client.CreateIndex(indexName, s => s          .NumberOfReplicas(replicas)          .NumberOfShards(shards)          .Settings(settings => settings             .Add("merge.policy.merge_factor", "10")             .Add("search.slowlog.threshold.fetch.warn", "1s")             .Add("mapping.allow_type_wrapper", true)             .Add("analysis.filter.trigrams_filter.type", "nGram")             .Add("analysis.filter.trigrams_filter.min_gram", "3")             .Add("analysis.filter.trigrams_filter.max_gram", "3")             .Add("analysis.analyzer.trigrams.type", "custom")             .Add("analysis.analyzer.trigrams.tokenizer", "standard")             .Add("analysis.analyzer.trigrams.filter.0", "lowercase")             .Add("analysis.analyzer.trigrams.filter.1", "trigrams_filter")           )           .AddMapping<Object>(mapping => mapping              .Type("data")              .AllField(af => af.Enabled())              .Properties(prop => prop                 .String(sprop => sprop                   .Name("text")                   .IndexAnalyzer("trigrams")                  )               )           )       );

Please note that NEST also includes the ability to create index settings using strongly typed classes as well. I will post an example of that later, if I have time to work through it.

Creating index with NEST 7.x

Please also note that in NEST 7.x CreateIndex method is removed. Use Indices.Create isntead. Here's the example.

_client.Indices    .Create(indexName, s => s        .Settings(se => se            .NumberOfReplicas(replicas)            .NumberOfShards(shards)            .Setting("merge.policy.merge_factor", "10")));

In case people have NEST 2.0, the .NumberOfReplicas(x).NumberOfShards(y) are in the Settings area now so specify within the lamba expression under Settings.

        EsClient.CreateIndex("indexname", c => c        .Settings(s => s             .NumberOfReplicas(replicasNr)             .NumberOfShards(shardsNr)        )

NEST 2.0 has a lot of changes and moved things around a bit so these answers are a great starting point for sure. You may need to adjust a little for the NEST 2.0 update.

Small example :

            EsClient.CreateIndex("indexname", c => c                .NumberOfReplicas(replicasNr)                .NumberOfShards(shardsNr)            .Settings(s => s                 .Add("merge.policy.merge_factor", "10")                 .Add("search.slowlog.threshold.fetch.warn", "15s")            )            #region Analysis           .Analysis(descriptor => descriptor                .Analyzers(bases => bases                    .Add("folded_word", new CustomAnalyzer()                    {                        Filter = new List<string> { "icu_folding", "trim" },                        Tokenizer = "standard"                    }                    )             .TokenFilters(i => i                         .Add("engram", new EdgeNGramTokenFilter                         {                             MinGram = 1,                             MaxGram = 20                         }                         )            )            .CharFilters(cf => cf                         .Add("drop_chars", new PatternReplaceCharFilter                         {                             Pattern = @"[^0-9]",                             Replacement = ""                         }            )            #endregion            #region Mapping Categories            .AddMapping<Categories>(m => m                .Properties(props => props                    .MultiField(mf => mf                            .Name(n => n.Label_en)                            .Fields(fs => fs                                .String(s => s.Name(t => t.Label_en).Analyzer("folded_word"))                                )                        )             )            #endregion    );