mirrorview的切换测试问题

Promo就是对换角色，secondary LUN如果原来已经挂接主机的话不用重新扫描，将I/O导入新的primary image (原secondary)即可。

Promoting with MirrorView/S

1. Quiesce I/O to the primary image.

2. Wait for the secondary image to become “Synchronized.”

3. Promote the secondary image.

4. Resume I/O to the new primary image (the previous secondary).

Promoting with MirrorView/A

1. Quiesce I/O to the primary image (an unmount recommended).

2. Perform an update, so that the secondary becomes “synchronized.”

3. Promote the secondary image.

4. Resume I/O to the new primary (previous secondary) image.

另外如果DR site之间连接已经down了的话，可以强制promo，但如果到一半连接又起来了，两边就会都是primary site，这时只能删掉MirrorView重建。