uhm invalid blocks happen because they are orphaned or someone else was first, not much can be done to resolve this
Better connected/faster servers reduce it a lot. 3 orphans in 24 hours is seems extremely high given the size of the pool. Orphan rates should be <1%. Obviously a given sample may have much more than 1% just due to lack of # of rounds being evaluated. Maybe organofcorti can shed some light on the probabilities.
EDIT: 2 of the 3 orphans were never even seen by Blockchain.info...that points to serious server issues. These blocks were either never broadcast, or were broadcast well after the prior block (meaning no connected peers accepted it and rebroadcasted). The timestamp on 265441 was more than 1 minute after the competing block was seen by Blockchain.info. The timestamp on 265419 was almost 4 minutes after. This may not be the real delay due to ntime rolling/slush's poold configuration/where the table get it's timestamp from. But those are both blocks that were not even seen by the rest of the network apparently.
Yeah, none of them show up on my log.
No clue what happened with those... from what I've seen over the last 18 months or so, Slush very rarely gets orphans.
I did notice this:
2013-10-23 19:22:43 received block 00000000000000051a828b0196663b7b82f33d9ec386e9da0a7d12c36f7c051b
2013-10-23 19:22:43 SetBestChain: new best=00000000000000051a828b0196663b7b82f33d9ec386e9da0a7d12c36f7c051b height=265588 log2_work=73.094444 tx=25887076 date=2013-10-23 19:22:38 progress=0.999999
2013-10-23 19:22:55 received block 00000000000000051a828b0196663b7b82f33d9ec386e9da0a7d12c36f7c051b
2013-10-23 19:22:55 ERROR: ProcessBlock() : already have block 265588 00000000000000051a828b0196663b7b82f33d9ec386e9da0a7d12c36f7c051b
2013-10-23 19:24:29 received block 00000000000000051a828b0196663b7b82f33d9ec386e9da0a7d12c36f7c051b
2013-10-23 19:24:29 ERROR: ProcessBlock() : already have block 265588 00000000000000051a828b0196663b7b82f33d9ec386e9da0a7d12c36f7c051b
this earlier block is more like it usually is:
2013-10-22 15:59:49 received block 000000000000000a53c17f3837f4a9b058eff44a8e0691074253214db196496b
2013-10-22 15:59:49 SetBestChain: new best=000000000000000a53c17f3837f4a9b058eff44a8e0691074253214db196496b height=265348 log2_work=73.054409 tx=25822202 date=2013-10-22 15:59:43 progress=1.000000
2013-10-22 15:59:50 received block 000000000000000a53c17f3837f4a9b058eff44a8e0691074253214db196496b
2013-10-22 15:59:50 ERROR: ProcessBlock() : already have block 265348 000000000000000a53c17f3837f4a9b058eff44a8e0691074253214db196496b