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* [DOCS] Fix missing id syntax * Update docs/reference/troubleshooting/common-issues/disk-usage-exceeded.asciidoc * fix id
140 lines
5.2 KiB
Text
140 lines
5.2 KiB
Text
[[fix-watermark-errors]]
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=== Fix watermark errors
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++++
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<titleabbrev>Watermark errors</titleabbrev>
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++++
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:keywords: {es}, high watermark, low watermark, full disk, flood stage watermark
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When a data node is critically low on disk space and has reached the
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<<cluster-routing-flood-stage,flood-stage disk usage watermark>>, the following
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error is logged: `Error: disk usage exceeded flood-stage watermark, index has read-only-allow-delete block`.
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To prevent a full disk, when a node reaches this watermark, {es} <<index-block-settings,blocks writes>>
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to any index with a shard on the node. If the block affects related system
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indices, {kib} and other {stack} features may become unavailable. For example,
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this could induce {kib}'s `Kibana Server is not Ready yet`
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{kibana-ref}/access.html#not-ready[error message].
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{es} will automatically remove the write block when the affected node's disk
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usage falls below the <<cluster-routing-watermark-high,high disk watermark>>.
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To achieve this, {es} attempts to rebalance some of the affected node's shards
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to other nodes in the same data tier.
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****
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If you're using Elastic Cloud Hosted, then you can use AutoOps to monitor your cluster. AutoOps significantly simplifies cluster management with performance recommendations, resource utilization visibility, real-time issue detection and resolution paths. For more information, refer to https://www.elastic.co/guide/en/cloud/current/ec-autoops.html[Monitor with AutoOps].
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****
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[[fix-watermark-errors-rebalance]]
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==== Monitor rebalancing
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To verify that shards are moving off the affected node until it falls below high
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watermark., use the <<cat-shards,cat shards API>> and <<cat-recovery,cat recovery API>>:
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[source,console]
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----
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GET _cat/shards?v=true
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GET _cat/recovery?v=true&active_only=true
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----
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If shards remain on the node keeping it about high watermark, use the
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<<cluster-allocation-explain,cluster allocation explanation API>> to get an
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explanation for their allocation status.
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[source,console]
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----
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GET _cluster/allocation/explain
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{
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"index": "my-index",
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"shard": 0,
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"primary": false
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}
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----
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// TEST[s/^/PUT my-index\n/]
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// TEST[s/"primary": false,/"primary": false/]
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[[fix-watermark-errors-temporary]]
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==== Temporary Relief
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To immediately restore write operations, you can temporarily increase
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<<disk-based-shard-allocation,disk watermarks>> and remove the
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<<index-block-settings,write block>>.
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[source,console]
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----
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PUT _cluster/settings
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{
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"persistent": {
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"cluster.routing.allocation.disk.watermark.low": "90%",
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"cluster.routing.allocation.disk.watermark.low.max_headroom": "100GB",
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"cluster.routing.allocation.disk.watermark.high": "95%",
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"cluster.routing.allocation.disk.watermark.high.max_headroom": "20GB",
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"cluster.routing.allocation.disk.watermark.flood_stage": "97%",
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"cluster.routing.allocation.disk.watermark.flood_stage.max_headroom": "5GB",
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"cluster.routing.allocation.disk.watermark.flood_stage.frozen": "97%",
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"cluster.routing.allocation.disk.watermark.flood_stage.frozen.max_headroom": "5GB"
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}
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}
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PUT */_settings?expand_wildcards=all
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{
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"index.blocks.read_only_allow_delete": null
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}
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----
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// TEST[s/^/PUT my-index\n/]
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When a long-term solution is in place, to reset or reconfigure the disk watermarks:
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[source,console]
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----
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PUT _cluster/settings
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{
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"persistent": {
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"cluster.routing.allocation.disk.watermark.low": null,
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"cluster.routing.allocation.disk.watermark.low.max_headroom": null,
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"cluster.routing.allocation.disk.watermark.high": null,
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"cluster.routing.allocation.disk.watermark.high.max_headroom": null,
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"cluster.routing.allocation.disk.watermark.flood_stage": null,
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"cluster.routing.allocation.disk.watermark.flood_stage.max_headroom": null,
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"cluster.routing.allocation.disk.watermark.flood_stage.frozen": null,
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"cluster.routing.allocation.disk.watermark.flood_stage.frozen.max_headroom": null
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}
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}
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----
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[[fix-watermark-errors-resolve]]
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==== Resolve
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To resolve watermark errors permanently, perform one of the following actions:
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* Horizontally scale nodes of the affected <<data-tiers,data tiers>>.
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* Vertically scale existing nodes to increase disk space.
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* Delete indices using the <<indices-delete-index,delete index API>>, either
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permanently if the index isn't needed, or temporarily to later
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<<snapshots-restore-snapshot,restore>>.
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* update related <<index-lifecycle-management,ILM policy>> to push indices
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through to later <<data-tiers,data tiers>>
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TIP: On {ess} and {ece}, indices may need to be temporarily deleted via
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its {cloud}/ec-api-console.html[Elasticsearch API Console] to later
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<<snapshots-restore-snapshot,snapshot restore>> in order to resolve
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<<cluster-health,cluster health>> `status:red` which will block
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{cloud}/ec-activity-page.html[attempted changes]. If you experience issues
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with this resolution flow on {ess}, kindly reach out to
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https://support.elastic.co[Elastic Support] for assistance.
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[discrete]
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[[fix-watermark-errors-prevent]]
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=== Prevent watermark errors
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To avoid watermark errors in future, perform one of the following actions:
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* If you're using {ess}, {ece}, or {eck}: Enable <<xpack-autoscaling,autoscaling>>.
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* Set up {kibana-ref}/kibana-alerts.html[stack monitoring alerts] on top of
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<<monitor-elasticsearch-cluster,{es} monitoring>> to be notified before
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the flood-stage watermark is reached.
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