# Splitting out Master / Data **URL:** \ **Category:** Elasticsearch\ **Created:** [December 18, 2011, 1:51pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187 "2011-12-18T13:51:47Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Garth](https://avatars.discourse-cdn.com/v4/letter/g/ba9def/32.png) [@Garth](https://discuss.elastic.co/u/Garth)\ **Post date:** [December 18, 2011, 1:51pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/1 "2011-12-18T13:51:47Z")
Is there any good reason to split out a Master node and Data node if both nodes are to be on the same server? ---
**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:** [December 20, 2011, 3:13pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/2 "2011-12-20T15:13:49Z")
No, you probably don't really want to run several instance son the same server. On Sun, Dec 18, 2011 at 3:51 PM, Garth [ghershfield.bah@gmail.com](mailto:ghershfield.bah@gmail.com) wrote: > Is there any good reason to split out a Master node and Data node if > both nodes are to be on the same server? ---
**Author:** ![Garth](https://avatars.discourse-cdn.com/v4/letter/g/ba9def/32.png) [@Garth](https://discuss.elastic.co/u/Garth)\ **Post date:** [December 22, 2011, 2:46pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/3 "2011-12-22T14:46:40Z")
I should have specified the following: 2 x 8 core servers w 192GB each. Yeah I know about the GC pause of Death! Would running several ES nodes ( master+data, not split out ) be viable and or it's really not good no matter what. Maybe 2 or 3 ES nodes w 50GB each per server. We have Fusion IO cards, so not worried about that. On Dec 20, 10:13 am, Shay Banon [kim...@gmail.com](mailto:kim...@gmail.com) wrote: > No, you probably don't really want to run several instance son the same > server. > > On Sun, Dec 18, 2011 at 3:51 PM, Garth [ghershfield....@gmail.com](mailto:ghershfield....@gmail.com) wrote: > > > Is there any good reason to split out a Master node and Data node if > > both nodes are to be on the same server? ---
**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:** [December 22, 2011, 6:02pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/4 "2011-12-22T18:02:03Z")
Yea, running multiple instances might make sense with so much memory, though I work really hard to behave nicely to GC, so it would be interesting to see how it behaves with a large heap. Note, if you want to run several instances on the same box, a feature needs to be added to make sure that a shard and a replica won't be allocated on the same _machine_ (not node), which is quite simple to add, can you open a feature? On Thu, Dec 22, 2011 at 4:46 PM, Garth [ghershfield.bah@gmail.com](mailto:ghershfield.bah@gmail.com) wrote: > I should have specified the following: 2 x 8 core servers w 192GB > each. Yeah I know about the GC pause of Death! Would running several > ES nodes ( master+data, not split out ) be viable and or it's really > not good no matter what. Maybe 2 or 3 ES nodes w 50GB each per server. > We have Fusion IO cards, so not worried about that. > > On Dec 20, 10:13 am, Shay Banon [kim...@gmail.com](mailto:kim...@gmail.com) wrote: > > > No, you probably don't really want to run several instance son the same > > server. > > > > On Sun, Dec 18, 2011 at 3:51 PM, Garth [ghershfield....@gmail.com](mailto:ghershfield....@gmail.com) > > wrote: > > > > > Is there any good reason to split out a Master node and Data node if > > > both nodes are to be on the same server? ---
**Author:** ![Berkay\_Mollamustafao](https://avatars.discourse-cdn.com/v4/letter/b/22d042/32.png) [@Berkay\_Mollamustafao](https://discuss.elastic.co/u/Berkay_Mollamustafao)\ **Post date:** [December 22, 2011, 6:33pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/5 "2011-12-22T18:33:49Z")
Garth, Would appreciate any info you may be able to provide on ES performance with Fusion IO, how it compares to normal hard drives, read/write rates etc. Regards, Berkay On Thursday, December 22, 2011, Garth [ghershfield.bah@gmail.com](mailto:ghershfield.bah@gmail.com) wrote: > I should have specified the following: 2 x 8 core servers w 192GB > each. Yeah I know about the GC pause of Death! Would running several > ES nodes ( master+data, not split out ) be viable and or it's really > not good no matter what. Maybe 2 or 3 ES nodes w 50GB each per server. > We have Fusion IO cards, so not worried about that. > > On Dec 20, 10:13 am, Shay Banon [kim...@gmail.com](mailto:kim...@gmail.com) wrote: > > > No, you probably don't really want to run several instance son the same > > server. > > > > On Sun, Dec 18, 2011 at 3:51 PM, Garth [ghershfield....@gmail.com](mailto:ghershfield....@gmail.com) wrote: > > > > > Is there any good reason to split out a Master node and Data node if > > > both nodes are to be on the same server? -- Regards, Berkay Mollamustafaoglu Ph: +1 (571) 766-6292 mberkay on yahoo, google and skype ---
**Author:** ![phobos182](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/phobos182/32/3011_2.png) [@phobos182](https://discuss.elastic.co/u/phobos182)\ **Post date:** [December 24, 2011, 4:47pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/6 "2011-12-24T16:47:06Z")
You have other issues with failure scenarios. Lets say you run 3-5x copies of ElasticSearch on one node. If that node crashes, you will have a lot of replication traffic to migrate off of the server to meet the replication agreement. Other issues arise from replica placement as Shay has stated. If you have 2/3 nodes placed on the same hosts, or even worse 3/3, then a crash of that system will cause a lot of availability / recovery issues. ---
**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:** [December 25, 2011, 4:31pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/7 "2011-12-25T16:31:27Z")
Assuming that we allow to define that a shard and a replica will not be allocated on the same "machine", then there ins't really a difference in terms of moving data around. Running 3 nodes on each machine is not different from running 1 node on each machine in terms of number of shards allocated on that machine. So when it fails, the same amount of shards / data will need to be moved. On Sat, Dec 24, 2011 at 6:47 PM, phobos182 [phobos182@gmail.com](mailto:phobos182@gmail.com) wrote: > You have other issues with failure scenarios. Lets say you run 3-5x copies > of > Elasticsearch on one node. If that node crashes, you will have a lot of > replication traffic to migrate off of the server to meet the replication > agreement. Other issues arise from replica placement as Shay has stated. If > you have 2/3 nodes placed on the same hosts, or even worse 3/3, then a > crash > of that system will cause a lot of availability / recovery issues. > > -- > View this message in context: > [http://elasticsearch-users.115913.n3.nabble.com/Splitting-out-Master-Data-tp3595620p3610768.html](http://elasticsearch-users.115913.n3.nabble.com/Splitting-out-Master-Data-tp3595620p3610768.html) > Sent from the Elasticsearch Users mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![phobos182](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/phobos182/32/3011_2.png) [@phobos182](https://discuss.elastic.co/u/phobos182)\ **Post date:** [December 26, 2011, 12:27am UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/8 "2011-12-26T00:27:15Z")
Usually I see this type of setup where an individuals runs one "gigantic" server with say, 12x1TB Hard drives, or 12x 2TB Hard Disks. If that system fails, then you would potentially have to replicate multiple terabytes of information. Not saying that every use would do this. Just a word of caution on creating gigantic servers while you could be better served with more - smaller servers. ---
**Author:** ![Garth](https://avatars.discourse-cdn.com/v4/letter/g/ba9def/32.png) [@Garth](https://discuss.elastic.co/u/Garth)\ **Post date:** [December 27, 2011, 5:07pm UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/9 "2011-12-27T17:07:32Z")
You guys bring up some good points with respect to recovery. We might go with VM's to the Fusion cards. If/when I have bench marks for Fusion I/O performance I will post that information. On Dec 25, 7:27 pm, phobos182 [phobos...@gmail.com](mailto:phobos...@gmail.com) wrote: > Usually I see this type of setup where an individuals runs one "gigantic" > server with say, 12x1TB Hard drives, or 12x 2TB Hard Disks. If that system > fails, then you would potentially have to replicate multiple terabytes of > information. > > Not saying that every use would do this. Just a word of caution on creating > gigantic servers while you could be better served with more - smaller > servers. > > -- > View this message in context:[http://elasticsearch-users.115913.n3.nabble.com/Splitting-out-Master-](http://elasticsearch-users.115913.n3.nabble.com/Splitting-out-Master-)... > Sent from the Elasticsearch Users mailing list archive at [Nabble.com](http://Nabble.com). ---
**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, 3:44am UTC](https://discuss.elastic.co/t/splitting-out-master-data/6187/10 "2017-07-06T03:44:17Z")