Sitecore fails when memory > maxmemory in Redis

Question

If you don't switch to another tier in time; Sitecore returns an Application error and is not available anymore. Monitoring Redis can be one solution, but are there any other options available?

See also: https://stackoverflow.com/questions/9987832/redis-with-resque-and-rails-err-command-not-allowed-when-used-memory-maxmemo

Server Error in '/' Application. ERR Error running script (call to f 7e0662727036231aea0363a485a8ee05e576df94): Causer script:2: Causer script: 2: -OOM command not allowed when used memory > 'maxmemory'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: StackExchange.Redis.RedisServerException: ERR Error running script (call to f_7e0662727036231aea0363a485a8ee05e576df94): @user_script:2: @user_script: 2: -0011 command not allowed when used memory. > 'maxmemory. Source Error: An unkandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [RedisServerException: ERR Error running script (call to f_7e0662727036231aea0363a485a8ee05e576df94): @user_script:2: @user_script: 2: -OOM command not allowed when used memory > 'maxmemory'. StackExchange.Redis.ConnectionMultiplexer.ExecuteSyncImpl(Message message, ResultProcessor'1 processor, ServerEndPoint server) +2886 StackExchange.Redis.RedisBase.ExecuteSync(Message message, ResultProcessor'1 processor, ServerEndPoint server) +122 StackExchange.Redis.RedisDatabase.ScriptEvaluate(String script, RedisKey[] keys, RedisValuen values, CommandFlags flags) +279 Sitecore.SessionProvider.Redis.<>c DisplayClass7.b 6() +55 Sitecore.SessionProvider.Redis.StackExchangeClientConnection.RetryForScriptNotFound(Func'1 redisOperation) +135 Sitecore.SessionProvider.Redis.StackExchangeClientConnection.RetryLogic(Func'1 redisOperation) +144 Sitecore.SessionProvider.Redis.StackExchangeClientConnection.Eval(String script, String[] keyArgs, Object[] valueArgs) +542 Sitecore.SessionProvider.Redis.RedisConnectionWrapper.Set(String sessionId, ISessionStateltemCollection data, Int32 sessionTimeout) +169 Sitecore.SessionProvider.Redis.RedisSessionStateProvider.SetAndReleaseItemExclusive(HttpContext context, String id, SessionStateStoreData item, Object lockld, Boolean newltem) +902 System.Web.SessionState.SessionStateModule.0nReleaseState(Object source, EventArgs eventArgs) +909 System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +142 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +92 I Version Information: Microsoft NET Framework Version:4.0.30319; ASP.NET Version:4.6.1590.0

Answer 1

from support: Some Azure resources can call automatically and some cannot, unfortunately, Redis is one that cannot scale. Sitecore XP has no way of knowing what size Redis cache the customer is using so you will either need to set up an Alert using Azure Monitor for when Redis gets within a certain threshold or you should just size up permanently.

You can automate the update of sizing using a Webhook or Logic App associated to the alert.