pull down to refresh
Yes. If you increased it to 80, you would have twice the time to resolve the connectivity, feerate or other issue before resorting to force closing the channel. So your odds of hitting that would drop by at least half I would think. It would benefit your other channels as well because all nodes can have these disagreements. A CLTV delta of 40 seems reasonable, but it doesn't hurt to give your channel a bit more leeway if you're having issues with force closes.
Still, this kind of papers over the problem, so it would be good to get as much data as possible if this happens again.
Edit: In this case it was the CLN timeout that hit. To update that one, adding cltv-delta=80 to your config should do the trick. I should note that you can also manually override the feerate acceptance rules for this particular channel using lightning-cli setchannel -k id=<channel id> ignorefeelimits=true. I wouldn't do this for any channel where you don't control the other side. If you can't punch the channel owner in the face, don't set it! It puts your channel's funds at risk.
Still, this kind of papers over the problem
I am not oppose to papering over problems. :)
To update that one, adding cltv-delta=80 to your config should do the trick. I should note that you can also manually override the feerate acceptance rules for this particular channel using lightning-cli setchannel -k id=<channel id>
ignorefeelimits=true.
Is CLTV-Delta measure in numbers of Block?
For Core Lightning does ride the lightning (or another tool) let this be set from the GUI or only Terminal?
Yes, CLTV delta is the number of blocks, so for example, you could add 12 to the default to give your node about 2 more hours to resolve any issues with an active htlc.
RTL should allow you to edit your node's config file, but it doesn't give access to all of the setchannel parameters (even though I think it uses it under the hood to set channel fees.)
If I was going to create a new channel between two nodes, which I have control over, would it make sense to increase the CLTV Delta to let the two nodes be more forgiving to each other?
I am understanding CLTV Delta correctly?
Looking at my other Node B channels, CLTV Delta is set to 40 which I assume is default as I have not adjusted them.