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OCI: Error "mount: can't read superblock on /dev/mapper/****" After Detaching iSCSI/Block Volume

in Linux

Applies To:

Oracle Cloud Infrastructure

Linux OS

Symptoms

When attempting to mount an LVM based filesystem using the command: 

$ sudo mount /dev/mapper/<LV> /u0X

the following error is encountered: 

mount: /u0X: can't read superblock on /dev/mapper/<LV>

Cause

This error occurs when the iSCSI block volume was previously detached without properly deactivating and unmounting the Logical Volume Manager (LVM) logical volumes present in the detached block volume. The improper handling leaves the filesystems present in the removed block volume in an inconsistent state, causing mount errors.

Solution

To safely unmount a block volume that contains a logical volume (LV), follow these steps:

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