# Will a rolling restart lose data? **URL:** \ **Category:** Elasticsearch\ **Created:** [April 17, 2010, 4:07pm UTC](https://discuss.elastic.co/t/will-a-rolling-restart-lose-data/2917 "2010-04-17T16:07:17Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Grant\_Rodgers](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/grant_rodgers/32/3204_2.png) [@Grant\_Rodgers](https://discuss.elastic.co/u/Grant_Rodgers)\ **Post date:** [April 17, 2010, 4:07pm UTC](https://discuss.elastic.co/t/will-a-rolling-restart-lose-data/2917/1 "2010-04-17T16:07:17Z")
I've been looking at the docs and couldn't find the answer to this, so I thought I'd ask the list. Say I've changed the configuration of my elasticsearch cluster, and I want to restart every node to pick up the new config. Is there a possibility of losing data? Seems like there could be if every machine that hosts a shard happens to be restarting at the same time. What's a good way to do a rolling restart without losing anything? Thanks! ---
**Author:** ![Clinton\_Gormley](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@Clinton\_Gormley](https://discuss.elastic.co/u/Clinton_Gormley)\ **Post date:** [April 17, 2010, 4:13pm UTC](https://discuss.elastic.co/t/will-a-rolling-restart-lose-data/2917/2 "2010-04-17T16:13:19Z")
> Say I've changed the configuration of my elasticsearch cluster, and I > want to restart every node to pick up the new config. Is there a > possibility of losing data? Seems like there could be if every > machine that hosts a shard happens to be restarting at the same time. > > What's a good way to do a rolling restart without losing anything? > From what I've seen of doing this in practise, before a node shuts down, > it syncs its data with the other nodes, and possibly tries to snapshot > the gateway (if required). So, shutdown one node, restart it, wait for the cluster\_health to be 'green' again (requires at least three running nodes, I think), then move on to the next node. clint ---
**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:** [April 17, 2010, 4:47pm UTC](https://discuss.elastic.co/t/will-a-rolling-restart-lose-data/2917/3 "2010-04-17T16:47:23Z")
When you shut down a node, shards allocated to it are reallocated to other nodes. When you start it up again, shards are redistributed to it. If, for example, you have set the number\_of\_replicas set to 1, then each shard will have a replica, meaning that is its assigned to a specific node, it will recover its state from another node that is running. If you have a gateway set, then the first shard will recover its state from the gateway. cheers, shay.banon On Sat, Apr 17, 2010 at 7:13 PM, Clinton Gormley [clinton@iannounce.co.uk](mailto:clinton@iannounce.co.uk)wrote: > > Say I've changed the configuration of my elasticsearch cluster, and I > > want to restart every node to pick up the new config. Is there a > > possibility of losing data? Seems like there could be if every > > machine that hosts a shard happens to be restarting at the same time. > > > > What's a good way to do a rolling restart without losing anything? > > > From what I've seen of doing this in practise, before a node shuts down, > > it syncs its data with the other nodes, and possibly tries to snapshot > > the gateway (if required). > > So, shutdown one node, restart it, wait for the cluster\_health to be > 'green' again (requires at least three running nodes, I think), then > move on to the next node. > > clint ---
**Author:** ![jimmy\_wen](https://avatars.discourse-cdn.com/v4/letter/j/c5a1d2/32.png) [@jimmy\_wen](https://discuss.elastic.co/u/jimmy_wen)\ **Post date:** [May 10, 2010, 10:39am UTC](https://discuss.elastic.co/t/will-a-rolling-restart-lose-data/2917/4 "2010-05-10T10:39:57Z")
where a complete cluster down happened , It will still lose data ,right? ---
**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, 4:24am UTC](https://discuss.elastic.co/t/will-a-rolling-restart-lose-data/2917/5 "2017-07-06T04:24:11Z")