Outbound Connections on Bitcoin Nodes: Why Limit at 10?

I just set up my node and saw that outbound connections start at zero and cap at 10. I noticed more peers mean faster sync. So if extra outbound connections could speed up sync further, why not raise that limit? Seems like more is better. Same goes for Bitcoin Core and Bitcoin Knot.

Not really that simple. The default of 10 (+1) is generally fine if a couple of peers are serving blocks quickly. Syncing isn’t just about download speed; it's also about verification and how fast your disk can handle it. If your hardware can't keep up, increasing outbound won't help. If it's slow, check for bottlenecks elsewhere.

It's designed this way on purpose. There are way fewer nodes that accept incoming connections. According to some stats, there are like 77k public nodes but only about 18k are reachable. If limits were higher, it could overload those reachable nodes.

You can speed up the initial block download for sure, but it won't be smooth all the time. Use SSDs for your chainstate. HDDs can work, but not great unless you have a lot of RAM to handle dbcache settings. Aim for a decent RAM setup to keep everything running without swapping.

Peak storage size is around 12.8GB, but whether it's 11GB or 12.8GB, the advice still stands regarding SSD and RAM.

I doubt more outbound peers will speed up syncing much. Bitcoin Core and Knot already fetch blocks in parallel from the best peers. After about 10 connections, the benefits are probably minimal, while CPU and network usage could increase. The default settings strike a balance between efficiency and performance.

Yeah, I didn't consider that chainstate might have been bigger back in the day. Thanks for that perspective! My Core nodes are set to allow other nodes to pull as much as they want, but I haven't seen any crazy pulls. Running through Tor might limit bandwidth too, but traffic is manageable.