Is there anyone would help me? The issue is:
a. created a software RAID5 with 4 disks
b. created a volume group with the md in step a
c. created a logical volume with vg in step b
d. plugged out 2 physical drives, which were the member of the software RAID5 in step a, the software RAID5 was offline.
there were two results:
1. could not delete the logical volume and volume group, when the plugged out disks did not contain the lvm metadata.
2. could not see the logical volume and volume group when i scan them, and could not delete the software RAID5, when the plugged out disks contained the lvm metadata.
And i made the md driver, exported the mddev_s.openers, and found the openers is not zero, so I could not delete the software RAID5.
Thank you very much.