The first stall symptom was discovered in zebrad 4.4.1. Because I didn’t know the exact details of the update, I had been under the misunderstanding that this problem only started occurring after the 4.5.0 update. I came to realize this fact after discovering fix/5709-sync-stall and reviewing the details once again. This was because I usually assumed that severe problems only arise along with a brand-new update. So, I am curious. Why did a problem suddenly occur in 4.4.1, which had been operating perfectly fine?
In the posts related to fix/5709-sync-stall, a “Degraded peer set” is mentioned as one of the causes of the stall. Does this mean that this issue has been inherent to zebrad since even before version 4.4.1? Or is it an explanation of something that happened recently in the middle of ongoing patches?
Source: https://github.com/ZcashFoundation/zebra/pull/10679
Degraded peer set. As more nodes stalled or ran old versions, at-tip peer ratio dropped as low as 2–5%. Fewer good peers means more misrouted requests hit peers that genuinely don’t have the block, accelerating the poisoning cascade.
Regarding “Why did this issue blow up right now?”, three causes were pointed out.
Personally, I cannot quite relate to the 1st cause. In my case, I have synced the node multiple times in the past and never experienced the stall symptom. When I first ran the node, I did get frustrated due to Linux being unfamiliar to me, but I didn’t feel any inconvenience regarding zebrad itself. Even in the 1.4 million to 2 million block range mentioned in the text, it just loaded the block information into my SSD a bit slowly, nothing more. As for the 3rd cause, it also fails to explain why zebrad 4.4.1 had been operating perfectly well until then, and why such a thing happened at a time that wasn’t right after an update.
The one that concerns me the most is the 2nd cause. Has there always been a lot of quality issues with zebrad up until now? I don’t know exactly when it started, but has the ratio of usable nodes been only around 2–5% recently? I started studying blockchain passionately this year. I am not an engineer, nor do I have any special talent for it, but I firmly believe that this will have a major impact on our daily lives. And I wanted to contribute to the ZEC network, which became my motivation to become a node operator. Therefore, I would love to know specifically what the current network situation of zebrad looks like—such as the hardships and challenges from the developers’ perspective.