Solana did not go down yesterday. It was still processing more than Ethereum and Bitcoin.

I'm not sure what is up with the modding here but it allows completely incorrect FUD to persist here. Solana never went down yesterday but did suffer from being a lot slower than normal, with bot spam of high compute transactions crowding blockspace. Blocks included votes as usual and less transactions than normal but tps also doesn't have much nuance since a Raydium transaction requires over 100x the compute of many Serum transactions, which means bots spamming Raydium transaction take up a lot of compute. The transaction fee model that they are moving to will take into account compute which will hopefully disincentivize spamming better. There are inefficiencies related to processing these more complex transactions which Solana Labs and contributors are working on addressing. Solana still does nearly 100k tps on testnet ddos tests but with transfer type transactions.

If you want to explore the actual blocks during the supposed outage yesterday you can use Solana Explorer to do so. Blocks included votes and a lesser amount of transactions -- "failed" transactions are not transactions which are in Solana's version of a mempool, which sometimes has over a million transactions waiting. A failed transaction can occur due a person not having required balance for example -- and failed transactions still pay a fee. https://explorer.solana.com/block/114782725

Lastly, Solana never "turned off" the network in September. If you think so you have been badly misinformed.

https://jumpcrypto.com/reflections-on-the-sept-14-solana-outage/