# Write heavy cluster, more RAM or CPU? **URL:** \ **Category:** Elasticsearch\ **Created:** [August 22, 2018, 8:39pm UTC](https://discuss.elastic.co/t/write-heavy-cluster-more-ram-or-cpu/145612 "2018-08-22T20:39:29Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![suanmeiguo](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/suanmeiguo/32/11758_2.png) [@suanmeiguo](https://discuss.elastic.co/u/suanmeiguo)\ **Post date:** [August 22, 2018, 8:39pm UTC](https://discuss.elastic.co/t/write-heavy-cluster-more-ram-or-cpu/145612/1 "2018-08-22T20:39:29Z")
I'm using EC2 instance. Looking at i3.2xlarge which gives a tons of storage, but wondering if that's the best for write heavy cluster. There will be maybe 70% insert/upsert, and 20% scan query, with probably just 10% get by id. All of these doesn't require a tons of storage, so I'm wondering if switching to some of the c5 or r5 instances is better? Any tips helps thanks a lot! ---
**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\ **Post date:** [August 22, 2018, 8:43pm UTC](https://discuss.elastic.co/t/write-heavy-cluster-more-ram-or-cpu/145612/2 "2018-08-22T20:43:39Z")
Indexing can be very I/O intensive, and i2 have fast disks, so should be appropriate. Best way to know is to benchmark your use case and see what resource that limits performance. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [September 19, 2018, 8:43pm UTC](https://discuss.elastic.co/t/write-heavy-cluster-more-ram-or-cpu/145612/3 "2018-09-19T20:43:42Z")
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