YugabyteDB needs max_clock_skew_usec set to 2x expected worst

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Set maxclockskew_usec to 2x your expected worst-case clock skew between nodes when starting YB-TServers and YB-Masters; e.g. 500000 for 250ms of expected skew. Keep clock drift under 500 PPM per node and run NTP or chrony everywhere. Never set the bound below what your hardware or cloud provider guarantees.

Context: Official deploy checklist: documents the gotcha that YugabyteDB needs maxclockskew_usec set explicitly when starting servers. Set it to two times the expected maximum clock skew between any two nodes. If you set it lower than the actual skew, nodes get stopped for availability or ACID consistency breaks.

Matched source

Source: Published skill Original query: "YugabyteDB needs maxclockskew_usec set to 2x expected worst skew" Key terms: clock, expected, needs, skew, usec, worst, yugabytedb

Source: Official deploy checklist: documents the gotcha that YugabyteDB needs maxclockskew_usec set explicitly when starting servers. Set it to two times the expected maximum clock skew between any two nodes. If you set it lower than the actual skew, nodes get stopped for availability or ACID consistency breaks.

Verified resolution: Set maxclockskew_usec to 2x your expected worst-case clock skew between nodes when starting YB-TServers and YB-Masters; e.g. 500000 for 250ms of expected skew. Keep clock drift under 500 PPM per node and run NTP or chrony everywhere. Never set the bound below what your hardware or cloud provider guarantees.

Source URL: https://github.com/ddhodge/yugabyte-db/blob/HEAD/docs/content/stable/deploy/checklist.md

Not specified by the original author.

If you see ERROR 40001 Restart read required, check clock sync between nodes first with NTP or chrony. Lowering maxclockskew_usec can reduce read latency, but only to a value your hardware or cloud provider guarantees in all situations; going below actual skew hurts availability or breaks consistency.

Context: YugabyteDB clock-skew writeup: documents the gotcha that ERROR 40001 Restart read required comes from clock skew between nodes, and the conservative 500ms default adds 500ms of latency to serializable read-only queries. Only lower maxclockskew_usec if your platform guarantees tighter skew, including restarts and VMotion.

Matched source

Source: Published skill Original query: "YugabyteDB ERROR 40001 Restart read required signals clock skew" Key terms: 40001, clock, error, read, required, restart, signals, skew, yugabytedb

Source: YugabyteDB clock-skew writeup: documents the gotcha that ERROR 40001 Restart read required comes from clock skew between nodes, and the conservative 500ms default adds 500ms of latency to serializable read-only queries. Only lower maxclockskew_usec if your platform guarantees tighter skew, including restarts and VMotion.

Verified resolution: If you see ERROR 40001 Restart read required, check clock sync between nodes first with NTP or chrony. Lowering maxclockskew_usec can reduce read latency, but only to a value your hardware or cloud provider guarantees in all situations; going below actual skew hurts availability or breaks consistency.

Source URL: https://Dev.to/yugabyte/observing-clock-skew-error-40001-restart-read-required-580j

Not specified by the original author.

Watch numtabletserverslive against your node count; a drop means a tablet server failed heartbeats or is partitioned, often from clock skew. If hybridclockskew is approaching hybridclock_error, fix clock sync on that host before reads start restarting. YSQL counters only move under load, so exercise the cluster before concluding metrics are broken.

Context: Instrumentation runbook: documents the gotcha that an idle YugabyteDB cluster shows no datapoints for YSQL counters, and that a dropped tablet server is the first suspect when numtabletserverslive falls below the node count. When hybridclockskew approaches hybridclock_error, the node is at risk of read restarts and stalls, so check NTP or chrony on that host.

Matched source

Source: Published skill Original query: "YugabyteDB tablet server drops and skew show up in server metrics first" Key terms: drops, first, metrics, server, show, skew, tablet, yugabytedb

Source: Instrumentation runbook: documents the gotcha that an idle YugabyteDB cluster shows no datapoints for YSQL counters, and that a dropped tablet server is the first suspect when numtabletserverslive falls below the node count. When hybridclockskew approaches hybridclock_error, the node is at risk of read restarts and stalls, so check NTP or chrony on that host.

Verified resolution: Watch numtabletserverslive against your node count; a drop means a tablet server failed heartbeats or is partitioned, often from clock skew. If hybridclockskew is approaching hybridclock_error, fix clock sync on that host before reads start restarting. YSQL counters only move under load, so exercise the cluster before concluding metrics are broken.

Source URL: https://github.com/base-14/docs/blob/HEAD/docs/instrument/component/yugabytedb.md