Persistent mounting of USB Devices
I've destroyed quite a few disks because the Linux kernel randomizes their mount points at each startup. So writing persistent mount rules using /etc/fstab is pointless because you never know where each one will be mounted after repeat reboots. We can achieve this in a different manner by using the following logic to determine their UUID property instead of using /dev/sdX names via the lsblk -f command:
[root@mbpc-pc mnt]# lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT
sdb linux_raid_member mbpc:0 2f36ac48-5e3e-4c54-7217-7c53bea3e41e
`-md0 LVM2_member ShnRBO-lz35-Zkh0-6piB-uzrU-Mqch-QoBdwc
`-MBPCStorage-MBPCBackup (dm-6) xfs MBPCBackupx 55d40be4-5e7c-4b49-af62-ac1ba09caaae /mnt/HTPCBackupXFS
sda linux_raid_member mbpc:0 2f36ac48-5e3e-4c54-7217-7c53bea3e41e
`-md0 LVM2_member ShnRBO-lz35-Zkh0-6piB-uzrU-Mqch-QoBdwc
`-MBPCStorage-MBPCBackup (dm-6) xfs MBPCBackupx 55d40be4-5e7c-4b49-af62-ac1ba09caaae /mnt/HTPCBackupXFS
sdc linux_raid_member mbpc:0 2f36ac48-5e3e-4c54-7217-7c53bea3e41e
`-md0 LVM2_member ShnRBO-lz35-Zkh0-6piB-uzrU-Mqch-QoBdwc
`-MBPCStorage-MBPCBackup (dm-6) xfs MBPCBackupx 55d40be4-5e7c-4b49-af62-ac1ba09caaae /mnt/HTPCBackupXFS
sdd linux_raid_member mbpc:0 2f36ac48-5e3e-4c54-7217-7c53bea3e41e
`-md0 LVM2_member ShnRBO-lz35-Zkh0-6piB-uzrU-Mqch-QoBdwc
`-MBPCStorage-MBPCBackup (dm-6) xfs MBPCBackupx 55d40be4-5e7c-4b49-af62-ac1ba09caaae /mnt/HTPCBackupXFS
sde linux_raid_member mbpc:0 2f36ac48-5e3e-4c54-7217-7c53bea3e41e
`-md0 LVM2_member ShnRBO-lz35-Zkh0-6piB-uzrU-Mqch-QoBdwc
`-MBPCStorage-MBPCBackup (dm-6) xfs MBPCBackupx 55d40be4-5e7c-4b49-af62-ac1ba09caaae /mnt/HTPCBackupXFS
sdf linux_raid_member mbpc:0 2f36ac48-5e3e-4c54-7217-7c53bea3e41e
`-md0 LVM2_member ShnRBO-lz35-Zkh0-6piB-uzrU-Mqch-QoBdwc
`-MBPCStorage-MBPCBackup (dm-6) xfs MBPCBackupx 55d40be4-5e7c-4b49-af62-ac1ba09caaae /mnt/HTPCBackupXFS
sdg
|-sdg1 ext4 1e14bdbf-0f27-49e9-8846-315da38d9aed /boot
|-sdg2 LVM2_member yfPtyW-SXEW-m0wU-hg1t-J5O6-E3Jr-TVyf1l
| |-mbpcvg-rootlv (dm-0) ext4 af6c5c11-6f1c-4735-8a7b-9869613de495 /
| |-mbpcvg-swaplv (dm-1) swap 141d7cb7-0ed0-4778-a174-3938d501ca0b [SWAP]
| `-mbpcvg-fmlv (dm-5) ext4 e02c14a4-5a03-4d9a-8e62-760119d749f2 /mnt/HTPCFileStorage
`-sdg3 LVM2_member c612Fm-haCB-DEJX-b29K-NZQc-L9Jo-pQECAd
|-VGEntertain-olv_swap (dm-2) swap 7169d9a4-cb74-4b8a-9818-d792f598d4a5
|-VGEntertain-oLogVol02 (dm-3) ext4 7956b19d-89be-40fc-b34b-12f12833c37c /mnt/HTPCFirstEntertainment/LogVol02
`-VGEntertain-olv_root (dm-4) ext4 00989ae4-3cc0-4467-a99b-0079ae0edd43 /mnt/HTPCFirstEntertainment/lv_root
sdj vfat 93E8-0250
`-sdj1
sdi
`-sdi1 vfat Lexar 5449-9578
sdk
`-sdk1 ntfs CENTON USB B80EDD970EDD4ECE
sdh
`-sdh1 vfat Lexar 543D-C137
sr0
sdl
`-sdl1 vfat 4CFE-820D
[root@mbpc-pc mnt]#
Next, we structure the /etc/fstab entries to use the UUID property to mount instead of the default device names that can fluctuate. Include also the right filesystem type:
UUID=93E8-0250 /mnt/FLASHDisk01 vfat context=system_u:object_r:samba_share_t:s0 0 2
UUID=5449-9578 /mnt/FLASHDisk02 vfat context=system_u:object_r:samba_share_t:s0 0 2
UUID=B80EDD970EDD4ECE /mnt/FLASHDisk03 ntfs context=system_u:object_r:samba_share_t:s0 0 2
UUID=543D-C137 /mnt/FLASHDisk04 vfat context=system_u:object_r:samba_share_t:s0 0 2
UUID=4CFE-820D /mnt/FLASHDisk05 vfat context=system_u:object_r:samba_share_t:s0 0 2
Then issue mount /mnt/FLASHDisk01 and so on to mount each one. To find out more details about each disk, we can now run the df -h command on each one like this:
[root@mbpc-pc mnt]# df -h FLASHDisk01
Filesystem Size Used Avail Use% Mounted on
/dev/sdj 30G 16K 30G 1% /mnt/FLASHDisk01
[root@mbpc-pc mnt]# df -h FLASHDisk02
Filesystem Size Used Avail Use% Mounted on
/dev/sdi1 30G 20M 30G 1% /mnt/FLASHDisk02
[root@mbpc-pc mnt]# df -h FLASHDisk03
Filesystem Size Used Avail Use% Mounted on
/dev/sdk1 30G 29G 1.5G 96% /mnt/FLASHDisk03
[root@mbpc-pc mnt]# df -h FLASHDisk04
Filesystem Size Used Avail Use% Mounted on
/dev/sdh1 30G 16K 30G 1% /mnt/FLASHDisk04
[root@mbpc-pc mnt]# df -h FLASHDisk05
Filesystem Size Used Avail Use% Mounted on
/dev/sdl1 126M 3.5M 122M 3% /mnt/FLASHDisk05
[root@mbpc-pc mnt]#
Earlier we also adjusted the samba configuration file to share out the disks to the rest of the home, so now we need to adjust the entries to something similar to the below:
[FLASHDisk01]
comment = FLASH Disk 01
path = /mnt/FLASHDisk01
valid users = root
public = no
writable = yes
browseable = yes
guest ok = no
printable = no
Followed by restarting the smb service using service smb restart or on newer systems, systemctl restart smb . Admittedly the naming convention is not too pretty but maintenance wise it is very easy esp when referencing missing disks or adding them back into windows mappings.
Cheers,
TK
