# Multiple data paths, Force Merge API and Disk Size

**URL:** <https://discuss.elastic.co/t/multiple-data-paths-force-merge-api-and-disk-size/100795>\
**Category:** Elasticsearch\
**Created:** [September 17, 2017, 3:02pm UTC](https://discuss.elastic.co/t/multiple-data-paths-force-merge-api-and-disk-size/100795 "2017-09-17T15:02:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![soaguru](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@soaguru](https://discuss.elastic.co/u/soaguru)\
**Post date:** [September 17, 2017, 3:02pm UTC](https://discuss.elastic.co/t/multiple-data-paths-force-merge-api-and-disk-size/100795/1 "2017-09-17T15:02:28Z")

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I have few questions relating to multiple data paths

1. Assume I have multiple data paths like below  
path.data: /mnt/first,/mnt/second

2. My application data will max use 15 TB data. So If I plan use the AWS EBS st1 of 16TB (that's the max it can go). Will there be any performance issues if I use a single disk of 16TB or should I assign multiple volumes (multiple data paths, say 2 x 8TB, or 4x4TB)? Is there any recommended best practice here # of paths one should use?

Thanks.

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**Author:** ![theuntergeek](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/theuntergeek/32/44961_2.png) [@theuntergeek](https://discuss.elastic.co/u/theuntergeek)\
**Post date:** [September 17, 2017, 4:23pm UTC](https://discuss.elastic.co/t/multiple-data-paths-force-merge-api-and-disk-size/100795/2 "2017-09-17T16:23:40Z")

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Regarding your first point, forceMerge is segments per shard. Since shards do not span data paths (not anymore--since 2.x, IIRC), a forceMerge will not cause issues in the way you are suggesting.

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**Author:** ![soaguru](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@soaguru](https://discuss.elastic.co/u/soaguru)\
**Post date:** [September 19, 2017, 3:34pm UTC](https://discuss.elastic.co/t/multiple-data-paths-force-merge-api-and-disk-size/100795/3 "2017-09-19T15:34:09Z")

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Thanks Aaron.

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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:** [October 17, 2017, 3:34pm UTC](https://discuss.elastic.co/t/multiple-data-paths-force-merge-api-and-disk-size/100795/4 "2017-10-17T15:34:26Z")

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