Locked file how to find

Well I run into this issue a lot.  I cannot unmount a partition.. or I cannot open a file because it’s locked and in use.  How do I see what has that file or mount locked?  Well since everything in Linux is a file you can list open files … which will show you what processes have certain files locked this is done with the lsof command.

For example on my Mythbox I want to see what has the /storage partition locked I would issue:

[root@linuxmonkey2 ~]# lsof | grep storage
mysqld     2285      mysql   13u      REG      253,0        124     325498 /var/lib/mysql/mythconverg/storagegroup.MYD
mysqld     2285      mysql   57u      REG      253,0       5120     325424 /var/lib/mysql/mythconverg/storagegroup.MYI
gnome-key  2887     mythtv  mem       REG      253,0      40808     502127 /usr/lib/libhal-storage.so.1.0.0
mythbacke  7126       root   18w      REG      253,2 1492874876    1523719 /storage/recordings/1007_20100421150000.mpg

From that you can see mysql, gnome-key and mythbackend all have open files inside storage I would have to kill them before unmounting.

Get LUN WWID on RHEL

Getting the LUN WWID on RHEL is critical when dealing with multiple different Storage systems.  You can use the scsi_id command to find a WWID

scsi_id -g -u -s /block/sdd

Will return the WWID of the devices.  In addition if you install device-mapper-multipath you can use the lssci tool to output all lun’s and what storage system they belong to.