On 9/12/2016 7:07 PM, 郑文兴 wrote: > So you mean if there is no more than 10G free space, Lucene/Solr will > delete some files to save the disk space? Or it will cause the > misbehave of Lucene/Solr?
If you do not have enough free disk space, and a segment merge takes place that requires more free space than you have, then the merge will fail. Merges are going to happen if you are adding/updating documents in your index. The Solr operation called "optimize" is known as "forceMerge" in Lucene. It forces a merge of the entire index down to (usually) one segment. Here's some more information: https://lucene.apache.org/core/5_3_2/core/org/apache/lucene/index/IndexWriter.html#forceMerge(int) Lucene will not delete files to free up space. The only way that a Lucene index ever gets smaller is through segment merging, which will temporarily *increase* the space used, until the merge is complete. Any deleted documents contained in the merging segments will be removed when the merge completes. > Please note that we have several shards/partitions under the same root > directory, so which way the following is true to us. Let's assume we > have 2 partitions, and A -> 10G, B->10G > > l do we have to make sure there are at least 20G disk space available? > > l Or we just need to make sure there are at least 10G disk space > available? > The extra space required for merging is detailed in the link above. At worst your index size might temporarily increase by a factor of four. Usually a full optimize (forceMerge) on an index that's not in the compound file format will only *double* the index size while it's running, but in some situations, it might require more. My own recommendation: If you only have one large index on a server, you should have enough space available for that index to triple in size. If you have many large indexes, having enough space for *all* your indexes to double in size at the same time is probably sufficient, but if you can arrange for more free space, that would be advisable. Thanks, Shawn --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org
