loadbalance切换节点时，可能会导致访问的网站速度变得很慢

[dev4u]

我有两台服务器，A美国、B新加坡，已经配置负载均衡。

开始，我通过A访问youtube，一切很正常，整个访问链路：客户端->服务器A->美国的youtube cdn站点。
因为网络原因，sslocal切换到了服务器B。这个时候访问的链路变成：客户端->服务器B->美国的youtube cdn站点。
很明显，后者的访问链路虽然能通，但是并不是最优的。

导致这个现象，我估计是因为sslocal把解析到的网站地址缓存在客户端，当客户端被切换另一台服务器的时候，之前解析到的ip地址缓存没有清空，仍用于后续的服务器创建链接用。

能不能优化一下这块缓存逻辑？

[zonyitoo]

You just make an assumption and then ask for a solution...

First of all, as you said, sslocal detected some network problems to server A, so it switches to server B. Although the access path through B is not the optimal, but sslocal will then switch back to A if the network between them is recovered.

I don't know what exactly setup you were using. sslocal won't do any cache about target addresses.

[dev4u]

我请教一下，sslocal解析完一个域名，在ttl有效期内服务器地址发生切换，用户再次访问这个域名时，sslocal会重新发起域名解析吗？

[database64128]

sslocal only resolves your shadowsocks server’s domain name. Depending on your setup, it’s either your browser, system resolver, or ssserver’s job to lookup the domains of the website you are visiting.

[dev4u]

我懂你的意思了，谢谢指教。

[database64128]

If you open F12 and switch to the network tab while watching a video on YouTube, you'll notice that query parameters to YouTube's video CDN include your public IP address. When your actual public IP changes (sslocal switches server), you'll start to see failed requests with error code 403. I believe this is the type of "slowdowns" you are seeing in your observations. After a while of failed attempts, the player self-refreshes and starts to use your new public IP, and content starts to come through again.

[dev4u]

是的。
虽然访问的链接带了我的public ip，但访问的google服务仍然是美国节点。实际上访问新加坡节点才是更优的，这在域名ttl有效期内，会一直保持从新加坡访问美国节点的情况。

[database64128]

I don’t think it has anything to do with geolocation. It’s just failed attempts (403s) from IP change.

[dev4u]

I don’t think it has anything to do with geolocation. It’s just failed attempts (403s) from IP change.

或许我能做的是修改返回更短的ttl长度。