Is the buffer amount published anywhere?
It's been 0 BTC for months now.
Probably won't ever have excess to build one.
(I was writing this before Luke-Jr replied, so, I'll post it anyway)
Eligius hasn't seen a positive buffer since.... hmm.... at least a year. So, buffer amount is essentially 0.
Fortunately this doesn't effect CPPSRB, since past miners' earnings don't affect active miners' earnings, like it did with the old SMPPS system where current miners would constantly struggle to catch up old extra credit.
It should be expected that, on average, any pool with 0% fee and a reward system that pays fairly would not have a buffer and instead would be continuously battling against long rounds and stale/orphaned blocks. Again, with Eligius and CPPSRB, this doesn't really hurt miners at all. Active miners will always have shares in the top 25 BTC of the CPPSRB share log, and will always be paid as much as possible from the blocks found.
And the shelved shares make it so that subsequent lucky rounds catch up the unlucky round's shares in a Last-in-first-out way. Overall, under CPPSRB, Eligius has managed to stay at or very close to 100% PPS.
In any case, the buffer amount is in fact exposed in the API files for the blocks. If you look at the bottom of
latest.json, you'll see a field labeled
funds. That is the amount, in base units (satoshi), that the pool has to add to the next block reward. Right now it fluctuates around from 0 to about 1000 satoshi, since not all shares always add up to exactly 25 BTC (vardiff, old shares with different values, etc). I don't expect this to change, since it is highly improbably (especially with the rising difficulty) that the older extra credit/shelved shares will ever be fully paid.
-wk