# Need clarity on recovery throttling parameters impacting snapshot restores

**URL:** <https://discuss.elastic.co/t/need-clarity-on-recovery-throttling-parameters-impacting-snapshot-restores/278199>\
**Category:** Elasticsearch\
**Tags:** snapshot-and-restore\
**Created:** [July 8, 2021, 2:43pm UTC](https://discuss.elastic.co/t/need-clarity-on-recovery-throttling-parameters-impacting-snapshot-restores/278199 "2021-07-08T14:43:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![shivani\_aggarwal](https://avatars.discourse-cdn.com/v4/letter/s/22d042/32.png) [@shivani\_aggarwal](https://discuss.elastic.co/u/shivani_aggarwal)\
**Post date:** [July 8, 2021, 2:43pm UTC](https://discuss.elastic.co/t/need-clarity-on-recovery-throttling-parameters-impacting-snapshot-restores/278199/1 "2021-07-08T14:43:32Z")

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Hi,  
Current version used - elasticsearch-oss 7.8.0  
Upgrading to: elasticsearch-oss 7.10.2

Elasticsearch [7.9 breaking change](https://www.elastic.co/guide/en/elasticsearch/reference/7.10/release-notes-7.9.0.html#breaking-7.9.0) mentions about Snapshot restore throttling. As per the change -

- Restoring from a snapshot now properly takes recovery throttling into account (i.e. the `indices.recovery.max_bytes_per_sec` setting).
- `max_restore_bytes_per_sec` setting changed from 40mb default to unlimited.

Can someone help to understand the following:

1. Is the parameter max\_restore\_bytes\_per\_sec only applicable to remote repositories like S3 or GCS as i can find the mention of this parameter only in [snapshot/restore plugins](https://www.elastic.co/guide/en/elasticsearch/plugins/master/repository-hdfs-config.html). I use local glusterfs volume attached to store the snapshots. Will this setting still be applicable?

2. How do both these parameters indices.recovery.max\_bytes\_per\_sec and max\_restore\_bytes\_per\_sec work together in throttling the snapshot restore operation in versions\>=7.9?

3. What was the behavior before 7.9? Was there no throttling at all and restore could run at any rate as per the given resources? If yes:

- The breaking change states that - `This means that no behavioral change will be observed by clusters where the recovery and restore settings had not been adapted from the defaults.`

- If throttling was not considered at all previously (i.e. versions \<7.9), restore would happen at a higher speed as per available resources.  
Now due to indices.recovery.max\_bytes\_per\_sec=40mb limit getting considered in later versions, restores would run much slower (40mbps). How is it not a behavioral change?

- How is the change in default value of max\_restore\_bytes\_per\_sec from 40mb to unlimited not causing a behavioral change?

Any pointers would be appreciated.  
Thanks!

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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:** [July 8, 2021, 6:24pm UTC](https://discuss.elastic.co/t/need-clarity-on-recovery-throttling-parameters-impacting-snapshot-restores/278199/2 "2021-07-08T18:24:50Z")

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> [@shivani\_aggarwal](#):
>
> 1. Is the parameter max\_restore\_bytes\_per\_sec only applicable to remote repositories like S3 or GCS

No, it applies to all restores.

> [@shivani\_aggarwal](#):
>
> 1. How do both these parameters indices.recovery.max\_bytes\_per\_sec and max\_restore\_bytes\_per\_sec work together

The minimum of the two applies.

> [@shivani\_aggarwal](#):
>
> What was the behavior before 7.9?

`max_restore_bytes_per_sec` applied, with a default of `40mb`.

> [@shivani\_aggarwal](#):
>
> How is it not a behavioral change?

Because the effective limit is 40MBps either way.

> [@shivani\_aggarwal](#):
>
> How is the change in default value of max\_restore\_bytes\_per\_sec from 40mb to unlimited not causing a behavioral change?

Because `indices.recovery.max_bytes_per_sec` now applies.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [August 5, 2021, 6:25pm UTC](https://discuss.elastic.co/t/need-clarity-on-recovery-throttling-parameters-impacting-snapshot-restores/278199/3 "2021-08-05T18:25:21Z")

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