{ "schemaVersion": 1, "title": "RDS配置方式の比較：説明と公式資料の対応", "edition": "rds-deployment-comparison-v1", "page": "/aws-saa-c03-practice#rds-deployment-comparison", "recordDate": "2026-09-20", "method": "2026年9月20日に取得したAWS公式6ページの本文と、この比較節の説明を照合した。", "production": "PASS QUESTが生成AIを用いて制作。専門家監修やAWS承認を表すものではない。", "limits": [ "対象はRDS for MySQL / PostgreSQLの学習例。Aurora、他エンジン固有の仕様、Multi-AZ DBクラスターから別途作成するread replicaは比較対象外。", "3つの選定ケースは架空の学習例であり、AWS環境の実機検証や負荷試験、費用・復旧時間・学習効果の測定ではない。", "この比較節の確認であり、既存の全問題・演習や全技術資料を再検証したものではない。", "取得した資料の本文SHA-256は資料取得時点の同一性を示す。後日のAWS資料の更新や各環境の対応を保証しない。" ], "sources": [ { "id": "multiaz-overview", "label": "Multi-AZの配置方式とスタンバイの読み取り", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html", "retrievedAt": "2026-09-20T13:58:51.898000Z", "sha256": "c0d92f02e094eb8a28dc5252ead45dce95f88412952ad5c71753d380ca8fabe7", "status": 200 }, { "id": "instance", "label": "DBインスタンス配置の同期複製と読取制約", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZSingleStandby.html", "retrievedAt": "2026-09-20T14:00:55.155000Z", "sha256": "8a87b5b1a64612c96f484bec411d5f74618af2e0e529b80980bd3331420f2ba3", "status": 200 }, { "id": "instance-failover", "label": "DBインスタンスの自動切替・DNS・再接続", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.Failover.html", "retrievedAt": "2026-09-20T14:00:55.351000Z", "sha256": "f5e9736231179ade3b3538a0bdd4e9354146e199a9a173d4b016b7fe64567a8c", "status": 200 }, { "id": "cluster", "label": "DBクラスターの構成・準同期・複製遅延", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html", "retrievedAt": "2026-09-20T13:58:52.091000Z", "sha256": "93b04dd6f6635a38a8b7a4ccaf799afa73183a15a147b8f57905488905273715", "status": 200 }, { "id": "read-replica", "label": "リードレプリカの非同期複製・用途・併用", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html", "retrievedAt": "2026-09-20T13:58:52.229000Z", "sha256": "e31a31c1d656d189b30da54139d0e712cbe4897d45ccc50999fdacfc89a23182", "status": 200 }, { "id": "cluster-endpoints", "label": "DBクラスターの接続先と切替", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts-connection-management.html", "retrievedAt": "2026-09-20T13:58:52.421000Z", "sha256": "30d45ebe629fec527145bc1f8dae4cb4dfdf52e0d9aabe2548be0ad79f234ea3", "status": 200 } ], "claims": [ { "id": "layout-readability", "summary": "Multi-AZ DBインスタンスは別AZのスタンバイ1台を読み取りに使わない。Multi-AZ DBクラスターは同一Regionの3AZにwriter1台・reader2台を置き、readerは読み取りと自動切替の対象になる。", "sections": ["Opening description", "Multi-AZ DB cluster architecture"], "scope": "RDS for MySQL / PostgreSQLを例に配置方式を区別する。Auroraおよびクラスターから別途作成するread replicaとは区別。", "checkedOn": "2026-09-20", "sources": [ { "id": "multiaz-overview", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html" }, { "id": "instance", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZSingleStandby.html" }, { "id": "cluster", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html" } ] }, { "id": "replication-consistency", "summary": "DBインスタンスのスタンバイは同期、Multi-AZ DBクラスターは準同期、DBインスタンスread replicaは非同期。クラスターは少なくとも1readerの確認を待つが、全readerへの変更適用完了を意味せず、読み取りの反映遅延があり得る。", "sections": [ "Multi-AZ DB instance deployments", "Multi-AZ DB cluster architecture", "Replica lag and Multi-AZ DB clusters", "How read replicas work" ], "scope": "準同期を全readerへの即時反映やlag=0の保証と解釈しない。", "checkedOn": "2026-09-20", "sources": [ { "id": "instance", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZSingleStandby.html" }, { "id": "cluster", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html" }, { "id": "read-replica", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html" } ] }, { "id": "failover", "summary": "DBインスタンスは対象障害時にスタンバイへ自動切替しDNS参照先が変更され、既存接続の再確立が必要。DBクラスターのwriter障害時はreaderが新writerへ自動昇格し、lagが切替時間にも影響する。read replicaを独立DBとして使うには明示的な昇格操作を行う。", "sections": [ "Failing over a Multi-AZ DB instance", "Setting the JVM TTL for DNS name lookups", "Replica lag and Multi-AZ DB clusters", "Use cases for read replicas", "High availability connections" ], "scope": "無停止・特定復旧時間・すべての障害時の自動復旧の保証ではない。read replicaの昇格運用と、Multi-AZの管理された自動切替を区別する。", "checkedOn": "2026-09-20", "sources": [ { "id": "instance-failover", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.Failover.html" }, { "id": "cluster", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html" }, { "id": "read-replica", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html" }, { "id": "cluster-endpoints", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts-connection-management.html" } ] }, { "id": "application-endpoints", "summary": "DBインスタンスはDNSと再接続を扱う。DBクラスターは書込/一般用途にwriter endpoint、読取分散にreader endpointを使う。reader endpointの振分単位は接続で、同じ接続内のSQL単位ではない。DBインスタンスread replicaへはアプリ側で対象の読み取り接続を分ける。", "sections": [ "Setting the JVM TTL for DNS name lookups", "Types of Multi-AZ DB cluster endpoints", "High availability connections", "How read replicas work" ], "scope": "フェイルオーバー直後にはreader endpointが一時的に新writerへ向く場合もある。既存セッションの継続や自動的なquery分離を保証しない。", "checkedOn": "2026-09-20", "sources": [ { "id": "instance-failover", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.Failover.html" }, { "id": "cluster-endpoints", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts-connection-management.html" }, { "id": "read-replica", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html" } ] }, { "id": "combined-goals", "summary": "可用性と読み取り分散の両方が必要な場合、Multi-AZ DBクラスターと、Multi-AZ DBインスタンスにread replicaを追加する構成の双方が候補になる。", "sections": [ "Multi-AZ DB cluster architecture", "Read replicas in a Multi-AZ deployment" ], "scope": "選定は当サイトの学習上の整理。対応engine/version/Region/instance class、変更範囲、接続、鮮度、費用を確認せず唯一解や最安構成とは判定しない。", "checkedOn": "2026-09-20", "sources": [ { "id": "cluster", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html" }, { "id": "read-replica", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html" } ] }, { "id": "cost-and-support", "summary": "DBインスタンスread replicaは通常のDBインスタンスとして課金される。Multi-AZ DBクラスターの対応はengine/version/Region/instance classにより異なる。", "sections": [ "Opening description", "Instance class availability for Multi-AZ DB clusters" ], "scope": "具体的料金、最安構成、個別環境での利用可否や移行方法を検証していない。", "checkedOn": "2026-09-20", "sources": [ { "id": "read-replica", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html" }, { "id": "cluster", "url": "https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html" } ] } ] }