{"id":110026,"date":"2023-10-19T08:54:42","date_gmt":"2023-10-19T15:54:42","guid":{"rendered":"https:\/\/www.backblaze.com\/blog\/?p=110026"},"modified":"2025-12-12T13:11:08","modified_gmt":"2025-12-12T21:11:08","slug":"load-balancing-2-0-whats-changed-after-7-years","status":"publish","type":"post","link":"https:\/\/www.backblaze.com\/blog\/load-balancing-2-0-whats-changed-after-7-years\/","title":{"rendered":"Load Balancing 2.0: What\u2019s Changed After 7 Years?"},"content":{"rendered":"\r\n
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What do two billion transactions a day look like? Well, the data may be invisible to the naked eye, but the math breaks down to just over 23,000 transactions every second. <\/strong>(Shout out to Kris Allen<\/a> for burning into my memory that there are 86,400 seconds in a day and my handy calculator!)\u00a0<\/p>\r\n\r\n\r\n\r\n

Part of my job as a Site Reliability Engineer (SRE) at Backblaze is making sure that greater than 99.9% of those transactions are what we consider \u201cOK\u201d (via status code), and part of the fun is digging for the needle in the haystack of over 7,000 production servers and over 250,000 spinning hard drives to try and understand how all of the different transactions interact with the pieces of infrastructure.\u00a0<\/p>\r\n\r\n\r\n\r\n

In this blog post, I\u2019m going to pick up where Principal SRE Elliott Sims<\/a> left off in his 2016 article on load balancing<\/a>. You\u2019ll notice that the design principles we\u2019ve employed are largely the same (cool!). So, I\u2019ll review our stance on those principles, then talk about how the evolution of the B2 Cloud Storage platform<\/a>\u2014including the introduction of the S3 Compatible API\u2014has changed our load balancing architecture. Read on for specifics.\u00a0<\/p>\r\n\r\n\r\n\r\n

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Editor\u2019s Note<\/h4>\r\n

We know there are a ton of specialized networking terms flying around this article, and one of our primary goals is to make technical content accessible to all readers, regardless of their technical background. To that end, we\u2019ve used footnotes to add some definitions and minimize the disruption to your reading experience.<\/p>\r\n<\/div>\r\n\r\n\r\n\r\n

What Is Load Balancing?<\/h2>\r\n\r\n\r\n\r\n

Load balancing is the process of distributing traffic across a network. It helps with resource utilization, prevents overloading any one server, and makes your system more reliable. Load balancers also monitor server health and redirect requests to the most suitable server.<\/p>\r\n\r\n\r\n\r\n

With two billion requests per day to our servers, you can be assured that we use load balancers at Backblaze. Whenever anyone\u2014a Backblaze Computer Backup or a B2 Cloud Storage customer\u2014wants to upload or download data or modify or interact with their files, a load balancer will be there to direct traffic to the right server. Think of them as your trusty mail service, delivering your letters and packages to the correct destination\u2014and using things like zip codes and addresses to interpret your request and get things to the right place.\u00a0\u00a0<\/p>\r\n\r\n\r\n\r\n

How Do We Do It?<\/h3>\r\n\r\n\r\n\r\n

We build our own load balancers using open-source tools. We use layer 4 load balancing with direct server response (DSR). Here are some of the resources that we call on to make that happen:\u00a0\u00a0<\/p>\r\n\r\n\r\n\r\n