Program.cs

using ZiggyCreatures.Caching.Fusion;

namespace WorkerService8;

public class Program
{
    public static async Task Main(string[] args)
    {
        IHost host = Host.CreateDefaultBuilder(args)
            .ConfigureServices(services =>
            {
                services.AddFusionCache(opts =>
                {
                    opts.DefaultEntryOptions.IsFailSafeEnabled = true;
                    opts.DefaultEntryOptions.Duration = TimeSpan.FromHours(1);
                    opts.DefaultEntryOptions.FailSafeMaxDuration = TimeSpan.FromSeconds(10);
                    opts.DefaultEntryOptions.FailSafeThrottleDuration = TimeSpan.FromSeconds(5);
                });

            })
            .Build();

        var cache = host.Services.GetRequiredService<IFusionCache>();
        await cache.GetOrSetAsync("key1", cacheFactoryGood, cacheSetup);
        await Task.Delay(TimeSpan.FromSeconds(11));
        await cache.GetOrSetAsync("key1", cacheFactoryGood, cacheSetup);
        await Task.Delay(TimeSpan.FromSeconds(11));
        await cache.GetOrSetAsync("key1", cacheFactoryGood, cacheSetup);

        // local functions
        static Task<CacheItem> cacheFactoryGood(CancellationToken cancellationToken)
        {
            Console.WriteLine("cacheFactoryGood fired");
            return Task.FromResult(new CacheItem());
        }

        static void cacheSetup(FusionCacheEntryOptions opts)
        {
            opts.Duration = TimeSpan.FromHours(1);
            opts.FailSafeMaxDuration = TimeSpan.FromSeconds(10);
            opts.FailSafeThrottleDuration = TimeSpan.FromSeconds(5);
        }
    }
}

internal class CacheItem
{
}

"cacheFactoryGood fired" will be printed to Console 3 times. Though only single time expected - Duration is 1hours

Hi, please see my asnwer ZiggyCreatures/FusionCache#115 (comment)