I have ingest pipeline , to remove field content to free up space like below :
var pipeResponse = await _client.Ingest.PutPipelineAsync<Document>("attachments", p => p
.Description("Document attachment pipeline")
.Processors(pr => pr
.Attachment(a => a
.Field(f => f.Content)
.TargetField(f => f.Attachment)
.IndexedChars(_indexedCharacters)
)
.Remove(r => r
.Field("content")))
);
But search query after this operation doesn't return anything eventhough there are documents which matches the query.