Will inconsistent machine configurations for three TiKV nodes affect performance?

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This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: TIKV三个节点的机器配置不一致会影响性能吗？

| username: TiDBer_XowwRd4a

We are planning to set up a TiDB cluster, but we don’t have enough machines. If the configurations of the TiKV machines vary greatly, will it affect the overall performance? Or do the three KV configurations need to be consistent?

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| username: buddyyuan | Original post link

Sure, set the parameters. The short board theory of the barrel. Just set all three to the minimum resources.

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| username: TiDBer_XowwRd4a | Original post link

Thank you for your answer!
So the performance of the cluster will be lowered to match the configuration of the lowest KV, is that what you mean?

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| username: buddyyuan | Original post link

Yes, that’s what it means.

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| username: tomsence | Original post link

The main issue is still disk performance.

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| username: TiDBer_XowwRd4a | Original post link

Hmm, there are many differences in disk performance. Currently, 2 machines have SSDs, while the rest do not.

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| username: songxuecheng | Original post link

It will affect the distribution of region leaders, and TiDB will score based on disk performance.

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| username: Jiawei | Original post link

It is recommended to keep everything consistent, with all disks being SSDs. Otherwise, when performing some upgrade or change operations later, the eviction of leaders might result in very long waiting times.