# R/w performance impact and replicas consistency while moving data

**URL:** <https://forums.foundationdb.org/t/r-w-performance-impact-and-replicas-consistency-while-moving-data/567>\
**Category:** Using FoundationDB\
**Created:** [July 13, 2018, 6:23am UTC](https://forums.foundationdb.org/t/r-w-performance-impact-and-replicas-consistency-while-moving-data/567 "2018-07-13T06:23:02Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![zhanghuan](https://avatars.discourse-cdn.com/v4/letter/z/5fc32e/32.png) [@zhanghuan](https://forums.foundationdb.org/u/zhanghuan)\
**Post date:** [July 13, 2018, 6:23am UTC](https://forums.foundationdb.org/t/r-w-performance-impact-and-replicas-consistency-while-moving-data/567/1 "2018-07-13T06:23:02Z")

</div>

If replica storage host down or add a new storage host, some shards will be moved to new replica, so what will happen if there are clients updating or reading the keys in the moving shard? how to guarantee the replicas consistency, will be the requests blocked util moving down?

Even more, how about the log server down?