# Load Balancing ### #1: Consistent Hashing Only using consistent hashing is suboptimal because it balances loads about as well as choosing a random server for each request, when the distribution of requests is equal. But if some content is much more popular than others, it can be worse than that. Consistent hashing will send all of the requests for that popular content to the same subset of servers ### #2: Round-Robin/Least-Connection These two simple strategies works great for stateless services since they guarantee that each server will get equal amount of requests. However, for stateful services, they are still less-than-ideal: without hashing, these two solutions do not fully utilize the caches. One way to mitigate this cache problem is to use global(regional) cache. More specifically, the servers keep local caches, but also fall back to a regional shared cache. Writes will be send to both in-memory cache and the regional cache. On read, the server will first check its local cache and, if not found, try to fetch from the regional cache. Unfortunately, such strategy scales poorly, the shared cache traffic grows linearly with the number of servers. ### #3: Consistent Hashing with bounded load --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://xzhu0027.gitbook.io/blog/misc/index/load-balancing.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.