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29 lines
1.2 KiB
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29 lines
1.2 KiB
Plaintext
// Module included in the following assemblies:
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//
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// * etcd/etcd-performance.adoc
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:_mod-docs-content-type: CONCEPT
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[id="etcd-disk-latency_{context}"]
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= Effects of disk latency on etcd
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An etcd cluster is sensitive to disk latencies. To understand the disk latency that is experienced by etcd in your control plane environment, run the `fio` tests or suite.
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Make sure that the final report classifies the disk as appropriate for etcd, as shown in the following example:
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[source,terminal]
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----
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...
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99th percentile of fsync is 5865472 ns
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99th percentile of the fsync is within the recommended threshold: - 20 ms, the disk can be used to host etcd
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----
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When a high latency disk is used, a message states that the disk is not recommended for etcd, as shown in the following example:
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[source,terminal]
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----
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...
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99th percentile of fsync is 15865472 ns
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99th percentile of the fsync is greater than the recommended value which is 20 ms, faster disks are recommended to host etcd for better performance
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----
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When you use cluster deployments that span multiple data centers that are using disks for etcd that do not meet the recommended latency, it increases the chances of service-affecting failures and dramatically reduces the network latency that the control plane can sustain. |