I had an application that required a lot of resources, so I changed the instance type from t2.micro to t3a.small. However, I reverted back to t2.micro, and now all my MySQL databases are missing. I have never executed a DROP DATABASE command.

Both the EBS volume and the EC2 instance are intact, and my other files are still present. However, when I access into MySQL, it shows that the databases have been completely reset.

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| RECOVER_YOUR_DATA  |
| mysql              |
| performance_schema |
+--------------------+

Here are the contents of /var/lib/mysql:

[root@ip-172-31-38-89 ec2-user]# ls -al /var/lib/mysql
total 176144
drwxr-xr-x  5 mysql mysql      157 Jul  8 21:23 .
drwxr-xr-x 42 root  root      4096 Apr 29  2021 ..
-rwxr-xr-x  1 mysql mysql       56 Mar  7  2021 auto.cnf
-rwxr-xr-x  1 mysql mysql 79691776 Jul  8 21:07 ibdata1
-rwxr-xr-x  1 mysql mysql 50331648 Jul  8 21:07 ib_logfile0
-rwxr-xr-x  1 mysql mysql 50331648 Mar  7  2021 ib_logfile1
drwxr-xr-x  2 mysql mysql     4096 Jul  8 14:33 mysql
srwxrwxrwx  1 mysql mysql        0 Jul  8 21:21 mysql.sock
drwxr-xr-x  2 mysql mysql     4096 Mar  7  2021 performance_schema
drwxr-xr-x  2 mysql mysql       78 Jul  8 13:05 RECOVER_YOUR_DATA

I had a database named spring which is now missing. This database contained important data. How can I recover it?

I also detached and reattached the EBS volume; could I have reattached it incorrectly?

[root@ip-172-31-38-89 spring]# df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        482M     0  482M   0% /dev
tmpfs           492M     0  492M   0% /dev/shm
tmpfs           492M  476K  492M   1% /run
tmpfs           492M     0  492M   0% /sys/fs/cgroup
/dev/xvda1       30G   21G   10G  67% /
tmpfs            99M     0   99M   0% /run/user/1000

I tried to replicate the issue by creating test database and changing the instance type, but this time the test database remained intact, so it seems that the instance type change is not the cause…