[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-08-28。"],[],[],null,["# Availability in Cloud SQL\n\n\u003cbr /\u003e\n\n[MySQL](/sql/docs/mysql/availability \"View this page for the MySQL database engine\") \\| PostgreSQL \\| [SQL Server](/sql/docs/sqlserver/availability \"View this page for the SQL Server database engine\")\n\n\u003cbr /\u003e\n\nThis page describes operations that impact availability in Cloud SQL.\n\nCloud SQL helps you maximize the uptime of your database without any\nchanges to your application. With a 99.99% uptime [SLA](/sql/sla) and\nnear-zero downtime for several planned operations,\nCloud SQL Enterprise Plus edition offers greater resilience and business continuity for your\napplications.\n\nMaximizing uptime means reducing the downtime for your database.\nDowntime is typically caused by both unplanned events and planned operations.\n\nUnplanned events and zonal outage\n---------------------------------\n\nFor applications that require high availability, we recommend configuring\nthe instance for regional availability, also referred to as the\nhigh availability (HA) configuration in Cloud SQL.\nFor more information about configuring high availability in Cloud SQL, see\n[About high availability (HA)](/sql/docs/postgres/high-availability).\n\nFor instances configured with regional availability, if the instance\nencounters a failure, then Cloud SQL automatically brings up the\ninstance in the secondary zone with the same IP address and\nno data loss so that applications can resume operations on the database.\nThis protects against unplanned events such as the failure of a single VM\nhost, or the failure of one or more infrastructure components that causes\nthe outage of an entire zone.\n\nCloud SQL high availability is available for both Cloud SQL Enterprise Plus edition and\nCloud SQL Enterprise edition.\n\nIf you don't configure regional availability for an instance, then the instance\nis configured for zonal availability, also referred to as a\nstandalone instance.\n\nCloud SQL recovers standalone instances (instances configured with zonal availability)\nfrom VM host failures automatically.\nHowever, Cloud SQL doesn't recover standalone instances from a zonal\noutage automatically. To re-establish a standalone instance in a healthy zone,\nyou must restore any standalone instances manually.\nYou can recover a standalone instance from a zonal outage manually by\nperforming either point-in-time-recovery or by promoting a read replica to\nbecome the standalone instance. For more information, see\n[Recovery options for standalone instances](/sql/docs/postgres/high-availability#recovery-options).\n\nPlanned operations with near-zero downtime\n------------------------------------------\n\nFor planned operations such as maintenance or some instance reconfigurations,\nCloud SQL Enterprise Plus edition offers near-zero downtime for\nprimary instances with no application changes or proxy requirements.\n\nThe following planned operations benefit from the near-zero downtime\non a Cloud SQL Enterprise Plus edition primary instance. These downtimes are applicable to\nboth standalone (zonal) and high availability (regional) instances.\n\n- [Maintenance](/sql/docs/postgres/maintenance#nearzero), which includes the\n following operations with sub-second downtime:\n\n - Automatic maintenance that Cloud SQL performs every quarter\n - Self-service maintenance that you can initiate at any time\n - Maintenance simulation that you can initiate to test the sub-second downtime behavior\n\n\u003c!-- --\u003e\n\n- Minor version upgrade\n - Minor version upgrades are part of automatic maintenance and happen with sub-second downtime\n\n\u003c!-- --\u003e\n\n- Instance scaling\n\n - Scale-up: Increase the compute size (vCPU, memory) of your Cloud SQL instance as frequently as needed\n - Scale-down: Reduce the compute size (vCPU, memory) of your\n Cloud SQL instance infrequently\n\n | **Note:** If you scale down your instance more than once during a three-hour period, then only the first scale down event benefits from near-zero downtime. Subsequent scale down events experience regular downtime.\n- [Data cache](/sql/docs/postgres/data-cache)\n\n - Enable or disable data cache as frequently as needed\n- [Edition upgrade](/sql/docs/postgres/upgrade-cloud-sql-instance-to-enterprise-plus-in-place)\n\n - Perform an in-place upgrade to Cloud SQL Enterprise Plus edition\n\nWhat's next\n-----------\n\n- Learn [about high availability (HA)](/sql/docs/postgres/high-availability)\n\n- [Enable or disable high availability (HA)](/sql/docs/postgres/configure-ha)\n\n- Read [about disaster recovery (DR)](/sql/docs/postgres/intro-to-cloud-sql-disaster-recovery)\n\n- View all the [Google Cloud services available in locations worldwide](/about/locations)."]]
