Batch create volumes form image using SAN, then we find some volumes create error.
The error is after initial_volume before copy_image_to_volume, the detail is we can't find the multipath device in host, so we can't move on to copy image.
Multipath device is exist, but it is not in the initial connection generated, it is a residual device, there is a problem.
The reason of Residual device generating, mainly because of batch operation to create the volume form image, there will be a large number of concurrent operation. The host side will initialize
and terminate volumes at the same time, and at the same time to rescan and remove the host devices.
Host to remove the equipment and SAN to remove mapping group is asynchronous atomic operations, concurrent, once inserted among the rescan device operation will generate garbage device on the host, this multipath device would be a bug.
After that, create volume from image use the same lunid, will reuse the device, and this device can't normal use, will lead to create error.
To sum up, the causes of the abnormal is relatively complex. To solve it, it is necessary to take into account from the source, clean up the residual device.
Fix proposed to branch: master
Review: https:/