Migration from One Server to Another

Zitat von Methanoid

I am dumb.. I didnt realise I could use GUI apps like Gparted using the VNC option... Can I fix this mess with Gparted?

Tricky question... Just a quick visualisation of what has gone wrong:

I assume some partition setup like this:

Partition 1 | Partition 2 | Partition 3

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZZZZZZZZZZZ

The above partitions are the ones, which the partition table defines. X Y and Z are the drive spaces that are occupied with data from the filesystem (fat, ext4, btrfs, ZFS, etc.).

By using parted to just shrink the partition, we got the following scenario:

Partition 1 | Partition 2 | Partition 3 | Unused disk space

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZZZZZZZZZZZ

Now the Partition 3 won't work, as part of the data for the filesystem is outside of the partition boundary.

Currently there is no data lost, just the partition table is messed up. This can be fixed by manually adjusting the partition table or using "parted rescue" or testdisk.

But there might be the case, that fsck or something else has corrupted the data (like creating a new partition and formatting it in the unused disk space). This is the bad case, where you probably need some data recovery tool (like photorec).

The correct way of shrinking is the following (which GParted does automatically):

Partition 1 | Partition 2 | Partition 3

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZZZZZZZZZZZ

Shrink the filesystem down first (resize2fs does this):

Partition 1 | Partition 2 | Partition 3

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZ

Then change the partition table to actually shrink the partition:

Partition 1 | Partition 2 | Partition 3 | Unused disk space

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZ

Enlarging a partition works the other way around. First the partition table is modified:

Partition 1 | Partition 2 | Partition 3

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZ

And now the filesystem is resized (again with resize2fs) according to the partition boundaries:

Partition 1 | Partition 2 | Partition 3

XXXXXXXXXXXXXXYYYYYYYYYYYYZZZZZZZZZZZZZZZZZZZ

Why is this necessary to know?
Because the resize2fs part changes actual data on the disk. As GParted does this automatically, it might overwrite something (i don't know, maybe it's smart), as usually the partition you expand is in a working state.

Therefore I would suggest the following steps:

1. Backup your partition tables before and after every attempt to fix something, as you maybe want to revert back at some point to an old partition table: https://www.cyberciti.biz/faq/…able-with-sfdisk-command/
2. Try "parted rescue" or testdisk to automatically recreate a working partition table
3. Try gparted
4. Recover your files the hard way using photorec or similar tools

Edit: Just for your information: You can use X11 tunneling to use GUIs via SSH: https://wiki.archlinux.org/index.php/OpenSSH#X11_forwarding

I'm glad to hear, that you've got your data back.

First of all, I would suggest to backup/download the most important files. If something else goes wrong and the rescue attempt fails (shit happens...), you at least can setup a new server manually.

Then check your partition setup. We want the unused space at the end of the disk. If we shrink a partition that is not the last, we also need to move other partitions to the front, so that the empty space is at the end (so the dd copy only leaves out unused disk space instead of some partitions).

Now you can shrink the partition with gparted. I would suggest to shrink it, so that only 1Gb of free space remains on the partitions (so the system can boot and run without a problem). This reduces the amount of data that needs to be transferred via dd.

now continue with your list of steps. The most important thing is to check, that the shrinking worked fine. Everything else doesn't risk your data, as you only read from the old servers harddisk.

And probably you won't reach your new server after booting, as it probably has a static IP, which is the one from the old server. So don't worry, if you don't reach it via SSH, you can still fix it via VNC. Just look up where your OS stores the IP address configuration.

Sincerely

7c00

Methanoid and afterwards you should apply for the "I‘m a fu***** Linux Guru Badge"!

I never had enough balls to shrink partitions. I always bought Servers with bigger disks

I have no experience with dd over the network. For the copying of the files, you maybe can use rsync to synchronize all the files.