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  • Apollon Oikonomopoulos's avatar
    Pause DRBD sync for OS install if not wait_for_sync · 41e1e79e
    Apollon Oikonomopoulos authored
    When wait_for_sync is set to False in LUInstanceCreate, Ganeti lets DRBD sync
    in the background while performing the rest of the installation steps,
    including OS installation.
    However, OS installation is a very disk-intensive task that intereferes badly
    with the background I/O caused by DRBD's initial sync. To this end, we pause
    the background sync before OS installation and unpause it afterwards, which
    yields a significant speed boost for OS installation. The following should be
    a) The user has requested not to wait for sync, i.e. the instance will be
       non-redundant for an unspecified interval anyway and delaying this by a
       couple of minutes is not a big compromise.
    b) This approach is also followed during disk wiping.
    Signed-off-by: default avatarApollon Oikonomopoulos <>
    [ simplify an if check]
    Signed-off-by: default avatarIustin Pop <>
    Reviewed-by: default avatarIustin Pop <>