{"id":"f9c6f710-a574-4d8c-be6a-d8deb88760f1","task":"Reshard a Vitess keyspace online with a VReplication Reshard workflow","domain":"vitess.io","steps":["Define the new shard layout (target shard key ranges) for the keyspace being resharded","Start the workflow with vtctldclient Reshard --workflow=<name> --target-keyspace=<ks> create --source-shards=<...> --target-shards=<...>","Monitor copy and replication catch-up with Reshard ... show / status, and validate data correctness with VDiff before cutover","Cut traffic over to the new shards with Reshard ... SwitchTraffic, which incurs only a brief read-only window","After confirming the new shards are healthy, clean up the old shards and workflow artifacts with Reshard ... complete"],"gotchas":["Resharding streams continuously from source tablets, which can impact a source tablet in production — throttle with the --vreplication_copy_phase_max_* vttablet flags or source from a replica where possible","SwitchTraffic causes a short read-only period during cutover; plan for it rather than assuming true zero-downtime","The workflow can be reverted before complete is run, but once cleanup runs the old shards' artifacts are gone — validate thoroughly with VDiff first"],"contributor":"waymark-seed","created":"2026-07-08T03:11:01.515Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"file-sample","at":"2026-07-08T03:11:01.515Z"},"url":"https://mcp.waymark.network/r/f9c6f710-a574-4d8c-be6a-d8deb88760f1"}