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cloud engineer

device

Filter Output of LSBLK

Here’s one way to display block devices, mountpoints and size using lsblk.

lsblk -a -p -n -d -e 230 -o NAME,MOUNTPOINT,SIZE

Here are the options.

  • -a = list all empty devices
  • -p = print full device paths
  • -d = do not print holder devices or slaves
  • -e = exclude devices as by a comma-separate list
  • -o = specify which columns to print, e.g. NAME,MOUNTPOINT,SIZE

The output.

/dev/sda             30G
/dev/sdb /data       50G

Here’s the man page.

GCP Identify Your Disks

Here’s how to identify your disks on the system to cross check with GCP Dashboard.

ls -l /dev/disk/by-id

Result:

[root@servername ~]# ls -l /dev/disk/by-id
total 0
lrwxrwxrwx. 1 root root  9 Sep 15 05:30 google-boot -> ../../sda
lrwxrwxrwx. 1 root root 10 Sep 15 05:30 google-boot-part1 -> ../../sda1
lrwxrwxrwx. 1 root root  9 Sep 15 05:30 google-persistent-disk-1 -> ../../sdb
lrwxrwxrwx. 1 root root  9 Sep 15 05:30 scsi-0Google_PersistentDisk_boot -> ../../sda
lrwxrwxrwx. 1 root root 10 Sep 15 05:30 scsi-0Google_PersistentDisk_boot-part1 -> ../../sda1
lrwxrwxrwx. 1 root root  9 Sep 15 05:30 scsi-0Google_PersistentDisk_persistent-disk-1 -> ../../sdb

Force Umount if Busy

If device is busy and you can’t umount it, try it with -l option (lazy unmount). Or you can force it.

# standard
umount /mnt/data
# lazy umount
umount -l /mnt/data
# force
umount -f /mnt/data

Lazy unmount is safer since it will detach immediately and clean up all references to the file system. Force is a bit more drastic.