- As the slaves are restarted for each testcase, take the opportunity to restore their databases to a known state with the help of the snapshot(s)
 - Count max number of slaves used in testcases
 - Use copy_install_db to speed up "Installing db" phase


mysql-test/mysql-test-run.pl:
  Count max number of slaves used for a test run and use that when installing slave databases etc.
  Use "copy_install_db" for all but the first db to install
  After having stopped the slave database, restore it's database files from the snapshot.