We added a 500GB 7.2K SATA/300 Hitachi Deskstar E7K500 16MB disk to one of our dev servers and partitioned using fdisk and formatted the partition with etx3. When we tried mounting the same, we got the following error :
[root@xyz user]# mount -t ext3 /dev/sdb1 /mysql
mount: /dev/sdb1 already mounted or /mysql busy
lsof didn’t provide any open files that might be linked to this problem or there was any “famd” running. Finally doing the following steps to remove the logical devices from the device-mapper driver helped us fix the problem.
[root@xyz user]# dmsetup ls
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab
(253, 0)
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab1
(253, 1)
[root@xyz user]# dmsetup remove
ddf1_44656c6c202020201028001510281f033832b7a2f6678dab1
[root@xyz user]# dmsetup ls
…