# Update dynamic/static properties with CCR

**URL:** <https://discuss.elastic.co/t/update-dynamic-static-properties-with-ccr/258144>\
**Category:** Elasticsearch\
**Tags:** ccr-cross-cluster-replication\
**Created:** [December 9, 2020, 3:17pm UTC](https://discuss.elastic.co/t/update-dynamic-static-properties-with-ccr/258144 "2020-12-09T15:17:08Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Armen\_Petrosyan](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/armen_petrosyan/32/80330_2.png) [@Armen\_Petrosyan](https://discuss.elastic.co/u/Armen_Petrosyan)\
**Post date:** [December 9, 2020, 3:17pm UTC](https://discuss.elastic.co/t/update-dynamic-static-properties-with-ccr/258144/1 "2020-12-09T15:17:08Z")

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Hi.

In the section replication mechanics [here](https://www.elastic.co/guide/en/elasticsearch/reference/7.x/xpack-ccr.html#ccr-replication-mechanics) I see below quote

> The follower index automatically retrieves some updates applied to the leader index, while other updates are retrieved as needed

1. I don't sure what is is **"as needed"** means. I think you should elaborate more in the documentation. And more interesting how this "as needed" works.

2. There are various settings, how I can understand which exactly properties are replicated and which no?

My use case is this  
I have leader cluster, application works with it. I am configuring follower - it acts ONLY as a backup cluster in case if I will my leader failed and I decided to switch to follower.

1. Can I be sure that this cluster settings are total copy of settings that were on my leader cluster?
2. How I can understand list of dynamic properties that are not replicated (for example num\_of\_replicas is not replicated)? I need it for the case of switch.

I tried to update mappings on leader cluster and saw that when I perform GET host:port/index/\_mappings - it immediately replicate this to follower.

If I update this again, without performing below get request - it is also replicated, but with some lag 20-30s.

1. Is it normal behavior? What is this lag or where it configured?

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [January 6, 2021, 3:17pm UTC](https://discuss.elastic.co/t/update-dynamic-static-properties-with-ccr/258144/2 "2021-01-06T15:17:23Z")

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