What do I do if the "Btrfs has been removed" error message appears? - Server Migration Center

Problem description

During the migration of an operating system, the "Btrfs has been removed" error message is reported.

Cause

The operating system to be migrated uses the Btrfs file system. However, Anolis or Alibaba Cloud Linux does not support the Btrfs file system and cannot read the files in the hard disk partition that uses the Btrfs file system. Therefore, the operating system fails to be migrated.

Solution

Connect to the Elastic Compute Service (ECS) instance whose operating system you want to migrate. For more information, see Connect to a Linux instance by using a password or key.

Run the following command to view the file system of each partition:

df -T

A command output similar to the following one is returned:

[root@iZbp104w56ovfyfxy9o**** ~]# df -T
Filesystem     Type     1K-blocks    Used Available Use%     Mounted on
devtmpfs       devtmpfs   3920472       0   3920472   0%     /dev
tmpfs          tmpfs      3931060       0   3931060   0%      /dev/shm
tmpfs          tmpfs      3931060     532   3930528   1%      /run
tmpfs          tmpfs      3931060       0   3931060   0%      /sys/fs/cgroup
/dev/vda1      ext4      41152812 2562508  36686596   7%      /
tmpfs          tmpfs       786216       0    786216   0%      /run/user/0
/dev/vdb1      btrfs      20971520 1048576  19922944  6%      /mnt/btrfs

Run the following command to back up files in the Btrfs partition to a non-Btrfs partition:
```
rsync -av /mnt/btrfs/ /backup
```
Run the following command to unmount the Btrfs file system:
```
umount /mnt/btrfs
```
Run the following command to uninstall the Btrfs module:
```
rmmod btrfs
```
After the error is resolved, run the SMC client and retry the migration job. For more information, see Run the SMC client.