# Clarify difference between opening/closing an index and a shard becoming active/inactive? **URL:** \ **Category:** Elasticsearch\ **Created:** [November 29, 2011, 9:15am UTC](https://discuss.elastic.co/t/clarify-difference-between-opening-closing-an-index-and-a-shard-becoming-active-inactive/6004 "2011-11-29T09:15:06Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Matt1](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/matt1/32/2986_2.png) [@Matt1](https://discuss.elastic.co/u/Matt1)\ **Post date:** [November 29, 2011, 9:15am UTC](https://discuss.elastic.co/t/clarify-difference-between-opening-closing-an-index-and-a-shard-becoming-active-inactive/6004/1 "2011-11-29T09:15:06Z")
I see in the logs that shards will become inactive "index-wise", and I was wondering if anybody could explain in a little detail what that means? In particular: 1. Is the shard is still available for searching? I'm assuming that's what the log message implies. 2. How long does it take for a shard to become active again? 3. Because (I'm assuming) it's still available for searching, it means it's still in memory? 4. I can see that there's a timer based management, where by default it's marked inactive after 30m, and this is configurable. Are there any other more hands-on (programmatic) management tools? I combed the docs pretty thoroughly but didn't see any. 5. What constitutes activity from this perspective? I'm assuming calculated from the last time a document was indexed to that shard, but I'm not sure. 6. What's the performance tradeoffs for tweaking the inactivity timer shorter or longer? I tried to list specific questions, but they all point to a general lack of knowledge about this part of ES, so I would love any kind of more general explanation of the entire mechanism. Cheers! Matt ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [November 29, 2011, 4:44pm UTC](https://discuss.elastic.co/t/clarify-difference-between-opening-closing-an-index-and-a-shard-becoming-active-inactive/6004/2 "2011-11-29T16:44:43Z")
Are you asking about closing an index, and at what stage the shards exists for it? If so, here is the answer, if not, explain the background better.... When you close an index, they take no resources on the cluster, except for disk size. Their data remain on the nodes, but, they are not available to search or index, and no resources (memory, file handles, ...). When you open an index, the first thing that will happen will be allocating the primary shards to the latest version that exists on specific nodes. A Lucene index will be opened (can take time), and the transaction log will be replayed. Then, the replica (if you have) will be allocated and sync'ed against the primaries (reusing existing nodes with the same data). So, what is the cost of opening an index? The main cost is opening the shard index files (Lucene wise), and applying the transaction log. You can't really change the time it takes to open the Lucene index (unless you index less data / fields), but you can send flush to the index before closing it, so there won't be a need to replay the transaction log. The "inactive" part that you see in the log is simply indexing buffer management among shards within the same node, nothing more. A smaller indexing buffer size is allocated for inactive shards (shards that have not been indexed to for a long time). -shay.banon On Tue, Nov 29, 2011 at 11:15 AM, Matt [matt.chu@gmail.com](mailto:matt.chu@gmail.com) wrote: > I see in the logs that shards will become inactive "index-wise", and I was > wondering if anybody could explain in a little detail what that means? In > particular: > > 1. Is the shard is still available for searching? I'm assuming that's what > the log message implies. > 2. How long does it take for a shard to become active again? > 3. Because (I'm assuming) it's still available for searching, it means > it's still in memory? > 4. I can see that there's a timer based management, where by default it's > marked inactive after 30m, and this is configurable. Are there any other > more hands-on (programmatic) management tools? I combed the docs pretty > thoroughly but didn't see any. > 5. What constitutes activity from this perspective? I'm assuming > calculated from the last time a document was indexed to that shard, but I'm > not sure. > 6. What's the performance tradeoffs for tweaking the inactivity timer > shorter or longer? > > I tried to list specific questions, but they all point to a general lack > of knowledge about this part of ES, so I would love any kind of more > general explanation of the entire mechanism. > > Cheers! > Matt ---
**Author:** ![Matt1](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/matt1/32/2986_2.png) [@Matt1](https://discuss.elastic.co/u/Matt1)\ **Post date:** [December 1, 2011, 5:35am UTC](https://discuss.elastic.co/t/clarify-difference-between-opening-closing-an-index-and-a-shard-becoming-active-inactive/6004/3 "2011-12-01T05:35:45Z")
Got it. I think that mostly answers my question. Will keep browsing the code. Cheers! ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 3:46am UTC](https://discuss.elastic.co/t/clarify-difference-between-opening-closing-an-index-and-a-shard-becoming-active-inactive/6004/4 "2017-07-06T03:46:50Z")