TheKoguryo's Tech Blog

3.6.5 Mount Block Volume

According to the OCI document, if there are two or more volume other than root volume, if the device name is mounted with the device name, the device name and the actual device may be different.As of January 10, 2019, the CONSISTENT Device Path function was released to ensure the response of the device after the server reversion and the actual device.In the unsupported images and instances, the mount ** method is used based on the UUID of ** volume as before.

• Consistent Device Paths for Block Volumes
  • Services: Block Volume
  • Release Date: Jan. 10, 2019
  • When you attach a block volume to an instance you can now optionally select a device path that will remain consistent between instance reboots. See Connecting to Volumes With Consistent Device Paths for more information.
  • 지원 대상
    • Instance made of Oracle-Provided Platform Image -Linux -based image -The image and details since November 2018 [Image Release Notes] (https://docs.oracle.com/en-us/iaas/images/) -Instance created after January 11, 2019

Mounting with Device Path

1. You can check the Device Path (/Dev/Oracleoci/OracleVDB) of the Block Volume that was previously Attached in the OCI console.

   

2. Connect the compute instance with ssh and check the device path.

   [opc@examplelinuxinstance ~]$ ls -la /dev/oracleoci/
   total 0
   drwxr-xr-x.  2 root root  140 Jan 10 07:25 .
   drwxr-xr-x. 20 root root 3200 Jan 10 07:25 ..
   lrwxrwxrwx.  1 root root    6 Jan 10 05:41 oraclevda -> ../sda
   lrwxrwxrwx.  1 root root    7 Jan 10 05:41 oraclevda1 -> ../sda1
   lrwxrwxrwx.  1 root root    7 Jan 10 05:41 oraclevda2 -> ../sda2
   lrwxrwxrwx.  1 root root    7 Jan 10 05:41 oraclevda3 -> ../sda3
   lrwxrwxrwx.  1 root root    6 Jan 10 07:35 oraclevdb -> ../sdb
   

3. Create a directory to mount

   sudo mkdir /mnt/vol1
   

4. /etc/fstab update

   sudo vi /etc/fstab Add the following contents based on the device path you confirmed by performing the command.

   According to the recommendations of the OCI document, the _netdev,nofail option must be added to reduce the impact of the failure of the mounted volume when the instance is restarted.

   • Use the _netdev and nofail Options

     sudo vi /etc/fstab
     

   • Update example

     Add a line of mount information at the bottom of the existing content.

     #
     # /etc/fstab
     # Created by anaconda on Wed Dec  1 01:55:42 2021
     ...
     
     ## https://docs.us-phoenix-1.oraclecloud.com/Content/Block/Tasks/connectingtoavolume.htm
     /dev/oracleoci/oraclevdb /mnt/vol1 xfs defaults,_netdev,nofail 0 2
     

5. Mount

   sudo mount -a
   

   • Mount result

     You can see that /dev/sdb is mounted on /mnt/vol1.

     [opc@examplelinuxinstance ~]$ sudo mount -a
     [opc@examplelinuxinstance ~]$ df -h
     Filesystem      Size  Used Avail Use% Mounted on
     devtmpfs        310M     0  310M   0% /dev
     tmpfs           341M     0  341M   0% /dev/shm
     tmpfs           341M  5.1M  336M   2% /run
     tmpfs           341M     0  341M   0% /sys/fs/cgroup
     /dev/sda3        39G  3.1G   36G   8% /
     /dev/sda1       200M  7.5M  193M   4% /boot/efi
     tmpfs            69M     0   69M   0% /run/user/0
     tmpfs            69M     0   69M   0% /run/user/1000
     tmpfs            69M     0   69M   0% /run/user/994
     /dev/sdb         50G   33M   50G   1% /mnt/vol1
     

6. Restart the instance

   Since it is added to /etc/fstab, it is automatically mounted even when the instance restarts. Check if it mounts without any problems as shown below. Even after restarting, you can see that it is mounted as /mnt/vol1.

   [opc@examplelinuxinstance ~]$ sudo reboot
   Connection to 146.56.171.40 closed by remote host.
   Connection to 146.56.171.40 closed.
   
   ubuntu@NOTEBOOK-WORK:~/.ssh$ ssh -i privateKey opc@146.56.171.xx
   Last login: Mon Jan 10 08:26:13 2022 from 223.62.21.xx
   [opc@examplelinuxinstance ~]$ df -h
   Filesystem      Size  Used Avail Use% Mounted on
   devtmpfs        310M     0  310M   0% /dev
   tmpfs           341M     0  341M   0% /dev/shm
   tmpfs           341M  5.0M  336M   2% /run
   tmpfs           341M     0  341M   0% /sys/fs/cgroup
   /dev/sda3        39G  3.1G   36G   8% /
   /dev/sda1       200M  7.5M  193M   4% /boot/efi
   /dev/sdb         50G   33M   50G   1% /mnt/vol1
   tmpfs            69M     0   69M   0% /run/user/0
   tmpfs            69M     0   69M   0% /run/user/1000
   

Mount with UUID

According to the OCI document, if there are more than one volume other than the root volume, the order in which the device name and the actual device correspond to each other may be different after the server restarts if the device name is mounted. So to be precise, I mount it based on the UUID of the Volume.

Please refer to the document below for related information.

• Connecting to a Volume > Traditional fstab Options