Solana has completed the investigation of the failure that occurred on February 25
From the report:
Several network services running custom block relay software inadvertently transmitted a huge amount of data several orders of magnitude larger than a normal block,
The network deduplication logic was able to cope with this, but this block was retransmitted to the network by block relay services.,
These retransmitted blocks overloaded the logic of deduplication of relay services, overloading the Turbine and significantly impairing the refinement.
