# Having 2 allocation IDs in in\_sync\_allocations when there are no replicas

**URL:** <https://discuss.elastic.co/t/having-2-allocation-ids-in-in-sync-allocations-when-there-are-no-replicas/385174>\
**Category:** Elasticsearch\
**Created:** [February 24, 2026, 9:52am UTC](https://discuss.elastic.co/t/having-2-allocation-ids-in-in-sync-allocations-when-there-are-no-replicas/385174 "2026-02-24T09:52:48Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![winter\_crescents](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/winter_crescents/32/146971_2.png) [@winter\_crescents](https://discuss.elastic.co/u/winter_crescents)\
**Post date:** [February 24, 2026, 9:52am UTC](https://discuss.elastic.co/t/having-2-allocation-ids-in-in-sync-allocations-when-there-are-no-replicas/385174/1 "2026-02-24T09:52:48Z")

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Hi

I am facing this issue where I had an index with an initial replication of 1. However, one year ago, due to disk storage issues I reduced the replication to 0.

One year later, I now run this operation: `GET /_cluster/state?filter_path=metadata.indices.my_index.in_sync_allocations.*,routing_table.indices.my_index.*` and I realised that there are 2 allocation IDs in `in_sync_allocations.0` even though there are 0 replicas. Tried to find documentation of this error but to no avail. Does anybody know what is happening here?

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**Author:** ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)\
**Post date:** [February 24, 2026, 10:16am UTC](https://discuss.elastic.co/t/having-2-allocation-ids-in-in-sync-allocations-when-there-are-no-replicas/385174/2 "2026-02-24T10:16:39Z")

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That’s ok, it just means you haven’t written to this shard since dropping the replica, so if the current primary fails then ES can still safely recover from either of the shard copies that existed back when you set `number_of_replicas: 0` if they should still exist.

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**Author:** ![winter\_crescents](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/winter_crescents/32/146971_2.png) [@winter\_crescents](https://discuss.elastic.co/u/winter_crescents)\
**Post date:** [February 24, 2026, 10:23am UTC](https://discuss.elastic.co/t/having-2-allocation-ids-in-in-sync-allocations-when-there-are-no-replicas/385174/3 "2026-02-24T10:23:14Z")

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That’s great news! Thanks for the swift response! Cheers