About upgrading the Memcached version of an instance
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This page describes how your Memorystore for Memcached instance behaves during a version
upgrade operation, how an upgrade operation can affect your application, and
when you should run an upgrade operation. To learn how to upgrade an instance's
Memcached version, see Upgrade the Memcached version of an instance.
Upgrading an instance has performance and storage implications for your
application.
Best practices for upgrading an instance's Memcached version
Upgrade your instance during periods of low instance traffic to minimize the impact of the full cache flush caused by the upgrade operation. To learn how to monitor instance traffic, see Monitor Memcached instances.
Version upgrade behavior
The Memcached instance undergoes a complete cache flush during a version upgrade operation. Multi-node
instances are partially available during the upgrade operation. You cannot downgrade the instance to an earlier version once it has been upgraded.
An upgrade operation also causes the nodes to undergo a short connection reset of a couple minutes, or less. Applications should incorporate retry logic in the code to be able to reconnect to the nodes. The discovery endpoint and memcached node endpoints remain the same.
Because of the short term connection break, there may be a small amount of stale or inconsistent data that didn't write or update to the cache for the short amount of time the Memcached node was unavailable.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[],[],null,["# About upgrading the Memcached version of an instance\n\nThis page describes how your Memorystore for Memcached instance behaves during a version\nupgrade operation, how an upgrade operation can affect your application, and\nwhen you should run an upgrade operation. To learn how to upgrade an instance's\nMemcached version, see [Upgrade the Memcached version of an instance](/memorystore/docs/memcached/upgrade-memcached-version).\n\nUpgrading an instance has performance and storage implications for your\napplication.\n\nBest practices for upgrading an instance's Memcached version\n------------------------------------------------------------\n\nUpgrade your instance during periods of low instance traffic to minimize the impact of the full cache flush caused by the upgrade operation. To learn how to monitor instance traffic, see [Monitor Memcached instances](/memorystore/docs/memcached/monitor-instances).\n\nVersion upgrade behavior\n------------------------\n\nThe Memcached instance undergoes a complete cache flush during a version upgrade operation. Multi-node\ninstances are partially available during the upgrade operation. You cannot downgrade the instance to an earlier version once it has been upgraded.\n\nAn upgrade operation also causes the nodes to undergo a short connection reset of a couple minutes, or less. Applications should incorporate retry logic in the code to be able to reconnect to the nodes. The discovery endpoint and memcached node endpoints remain the same.\n\nBecause of the short term connection break, there may be a small amount of stale or inconsistent data that didn't write or update to the cache for the short amount of time the Memcached node was unavailable."]]
