title: Upgrade to postgres 10 wanting to use checksums
body: <p>I have a postgresql 9.3 instance that I am wanting to upgrade to postgresql 10. I have a command that I think should work but it includes checksums in it. My old instance doesn't have checksums enabled (could it even be at all? Forget was too long ago) and that is preventing my dry run from working right.</p>
  
  <p><strong>Error message</strong></p>
  
  <pre><code>Performing Consistency Checks on Old Live Server
  ------------------------------------------------
  Checking cluster versions                                   ok
  
  old cluster does not use data checksums but the new one does
  Failure, exiting
  </code></pre>
  
  <p><strong>My command stripped of real paths</strong></p>
  
  <pre><code>time ${PGBINNEW}/pg_upgrade --old-bindir=${PGBINOLD} --new-bindir=${PGBINNEW} --old-datadir=${PGDATAOLD} --new-datadir=${PGDATANEW} --old-port=${PGPORT} --new-port=${PGPORT} --jobs=$(nproc | awk '{ {print ($1 &gt; 4) ? 4 : ($1 == 1 ? 1 : $1 - 1)} }') --link --username=postgres --check
  </code></pre>
  
  <p>What can I do to resolve this?</p>