Many thanks.

On Fri, Mar 19, 2021 at 11:47:09AM +0800, 钱非凡 wrote:
> Thanks for replying, rich.
>
> here are some informations i gathered. the guest is linux (centos) and i find
> out the guest's file system is 'xfs' using `df -hT`:
>
> ```
> $ df -hT
> Filesystem              Type      Size  Used Avail Use% Mounted on
> /dev/mapper/centos-root xfs       8.0G  1003M  7.1G   13% /
> devtmpfs                devtmpfs  484M     0  484M    0% /dev
> tmpfs                   tmpfs     496M     0  496M    0% /dev/shm
> tmpfs                   tmpfs     496M  6.8M  489M    2% /run
> tmpfs                   tmpfs     496M     0  496M    0% /sys/fs/cgroup
> /dev/vda1               xfs      1014M  132M  883M   14% /boot
> tmpfs                   tmpfs     100M     0  100M    0% /run/user/0
> ```
>
> and sgdisk version is 0.8.10:
>
> ```
> $ sgdisk --version
> GPT fdisk (sgdisk) version 0.8.10
> ```
>
> also, i tried the command you gave. it came out the same output:
>
> ```
> $ virt-rescue --ro -d 138093b9b33345c38e58efa014036bd8
> ><rescue> sgdisk /dev/sdb -i 1
> Invalid partition data!
> ```

Yup, basically sgdisk thinks the partition is invalid.  Version 0.8.10
is really ancient - from 2014, so I'd start with a newer version.

Rich.

> but strange things happened when i tried some other reports' suggestions:
>
> https://listman.redhat.com/archives/libguestfs/2016-February/msg00145.html
> https://listman.redhat.com/archives/libguestfs/2018-November/msg00026.html
>
> i did these things:
>
> 1. set LIBGUESTFS_BACKEND to direct;
> 2. recompile the `libguestfs-1.40.2-10.el7.src.rpm` without the `
> XXXX-RHEL-7-Reject-use-of-libguestfs-winsupport-features-.patch `;
> 3. run the `virt-rescue` command again.
>
> ```
> $ virt-rescue --ro -d 138093b9b33345c38e58efa014036bd8
> ><rescue> sgdisk /dev/sdb -i 1
> Creating new GPT entries.
> Partition #1 does not exist.
> ```
>
> and the command works somehow. apparently, i still dont understand what
> happened indeed. and i have read about the official explanation of
> LIBGUESTFS_BACKEND, is this something to do with libvirt? is it a bug or
> something?
>
> https://libguestfs.org/libguestfs-test-tool.1.html#
> trying-out-with-without-libvirt

It's unlikely that libguestfs or libvirt or the backend has anything
to do with this.

The partition is corrupt and/or ancient sgdisk has a bug.

Rich.

--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
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