两个问题：
mdadm刚创build的数组不需要同步，因为它上面没有数据呢？ 也就是说，基本上是把它变成一种状态，它假定“数据”（即广阔的空白空间）是同步的，只是同步元数据？ 您可以使用--assume-clean选项。 从man ：
Tell mdadm that the array pre-existed and is known to be clean. It can be useful when trying to recover from a major failure as you can be sure that no data will be affected unless you actually write to the array. It can also be used when creating a RAID1 or RAID10 if you want to avoid the initial resync, however this prac‐ tice — while normally safe — is not recommended. Use this only if you really know what you are doing. When the devices that will be part of a new array were filled with zeros before creation the operator knows the array is actually clean. If that is the case, such as after running bad‐ blocks, this argument can be used to tell mdadm the facts the operator knows.