title: Does Orderer have Block(Ledger) data?
body: <p>I built hyperledger fabric network using Kafka-based Ordering Service.</p>
  
  <p>I thought that Orderer doesn't have Block data.<br/>
  But, when I checked /var/hyperledger/production/orderer/chains/mychannel in Orderer server, I found blockfile_000000 file.<br/>
  I checked this file using "less" command.<br/>
  Then, I found key-value data which I registered by invoking chaincode.</p>
  
  <p>What is this file?<br/>
  This means that Orderer also maintain Block data(i.e. Ledger)?</p>