can't boot up after changed vm machine type from n1-standard-1 to n2-standard-2

[todamoon btc]

my vm can't boot up after i changed vm machine type from n1-standard-1 to n2-standard-2, why? how can i do? Will i lose all my data？ Anyone help me? please! 

---serial port 1 log

[    1.689313] List of all partitions:

[    1.689957] No filesystem could mount root, tried: 

[    1.691175] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

[    1.692805] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.10.0-1062.18.1.el7.x86_64 #1

[    1.694755] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

[    1.696474] Call Trace:

[    1.697152]  [<ffffffffa997b416>] dump_stack+0x19/0x1b

[    1.698071]  [<ffffffffa9974a0b>] panic+0xe8/0x21f

[    1.699102]  [<ffffffffa9f89790>] mount_block_root+0x291/0x2a0

[    1.700215]  [<ffffffffa9f897f2>] mount_root+0x53/0x56

[    1.700977]  [<ffffffffa9f89931>] prepare_namespace+0x13c/0x174

[    1.702131]  [<ffffffffa9f8940e>] kernel_init_freeable+0x222/0x249

[    1.703160]  [<ffffffffa9f88b1f>] ? initcall_blacklist+0xb0/0xb0

[    1.704197]  [<ffffffffa9969c10>] ? rest_init+0x80/0x80

[    1.705175]  [<ffffffffa9969c1e>] kernel_init+0xe/0x100

[    1.706788]  [<ffffffffa998dd1d>] ret_from_fork_nospec_begin+0x7/0x21

[    1.708216]  [<ffffffffa9969c10>] ? rest_init+0x80/0x80

[    1.710131] Kernel Offset: 0x28200000 from 0xffffffff81000000 (relocation range: 0xffffffff

[Frederic Gervais]

Hello todamoon,

From reading the log, I can see this line [1] that indicated the kernel is not able to mount the filesystem. Solutions to this error message can be found here [2].

If the only thing you want to do is gain access to the information on the disk, you can do so by following these instructions [3] to detach the disk. You can then reattach the disk to a different instance as a “Additional disks”.

After booting the second instance, you will be able to access the data on the boot disk that is not working.

Frederic

[1] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

[2] https://askubuntu.com/questions/41930/kernel-panic-not-syncing-vfs-unable-to-mount-root-fs-on-unknown-block0-0

[3] https://cloud.google.com/compute/docs/disks/detach-reattach-boot-disk#detach_disk