When a Mastodon instance defederates another instance, incoming activities from that instance stop arriving. But the effect on your own server can be subtle, especially if you are not actively monitoring federation logs. One reliable way to detect a defederation is by examining Sidekiq queue patterns. Sidekiq is the background job processor that Mastodon uses … Read more
When your Mastodon instance grows, the federation object cache can consume excessive RAM. This cache stores remote posts, profiles, and media metadata from other instances. Without tuning, it may cause out-of-memory errors or force the server to swap heavily. This article explains what the federation object cache is, why it grows large, and how to … Read more
When you view a remote post in Mastodon, your instance caches a copy. Sometimes that cached copy becomes outdated or fails to load fully, showing a generic error or missing content. This happens because Mastodon fetches remote posts lazily and does not automatically refresh them. This article explains how to force your instance to re-fetch … Read more
When Mastodon instances communicate with each other, they rely on Webfinger lookups to resolve user addresses like user@example.com into local profile data. Each lookup result is cached to reduce network load and speed up subsequent requests. The default cache Time to Live (TTL) controls how long this data stays fresh before the system re-fetches it. … Read more
When your Mastodon server cannot communicate with other instances, content may fail to arrive in federated timelines or direct messages may not reach their destination. These failures are caused by network timeouts, SSL certificate mismatches, protocol version incompatibilities, or remote server rate-limiting. This article explains how to access and interpret federation error logs from the … Read more
When you follow a user on a remote Mastodon instance for the first time, you may notice that their older posts do not immediately appear in your Home timeline. This is not a bug or a missing feature—it is a deliberate design choice to control server load and bandwidth usage. The mechanism that controls how … Read more
When you follow a new account on Mastodon, the server does not automatically fetch that account’s past posts. This means your federated timeline may show only new posts from that account, leaving a gap in your feed. The missing older content is not a bug but a design choice to reduce server load and storage … Read more
Mastodon instances exchange posts and activities through federation. When a popular account on a remote instance posts, your instance must process that activity for every local follower. This can cause a sudden flood of jobs in Sidekiq, the background job processor, leading to high memory usage, queue backlogs, and degraded performance. The root cause is … Read more
Mastodon relies on federation to deliver posts, likes, and boosts to remote servers. When a remote server is slow or under heavy load, your posts may take minutes or even hours to appear there. This delay happens because Mastodon queues outgoing deliveries and retries them with backoff timers. This article explains how to adjust server-side … Read more
Mastodon instances periodically refresh their connection to other servers to keep the federated timeline up to date. This background refresh process pulls new posts, boosts, and replies from remote instances that your users follow or interact with. Without a properly configured refresh schedule, your instance may show stale content or miss updates from the broader … Read more