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I can't understand where are these events log data is stored?

I can access to my logs by 

myContract.allEvents({
    fromBlock: 2139049,
    toBlock: 'latest'
  }, function(error, event){
      console.log("event : ",event);
});

But, can i access this logs after one year? Or they'll be removed? And where is this logs are storing?

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Event logs are stored within transaction receipts, which are stored in blocks. You will be able to access your event logs for as long as the network remains active.

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  • Is there reason do not use event log for storing some data? I just need to store ipfs hash in each transaction, and later return those hashes in correct order. As i understand, reason is that contract can't access event log itself?
    – user25688
    Commented Apr 19, 2018 at 19:40
  • It is fairly common practice for a dApp to read data from contract event logs (rather than from the contract), as it is often a cheaper form of storage. You are correct in that the contract cannot access the event log directly. As for returning the hashes/events in the correct order, I do not believe web3 does this by default.
    – Zack McGinnis
    Commented Apr 19, 2018 at 19:48
  • I will order it by frontend js scripts. I'm very surprised, since I read that the logs are stored on the nodes and they can retire. If it's not, so this is very cool, because of cheap
    – user25688
    Commented Apr 19, 2018 at 22:07
  • Event logs will always be recoverable since transaction receipts are stored within blocks.
    – Zack McGinnis
    Commented Apr 19, 2018 at 22:23

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