[SOLVED] proxmox 4.2 disks migration - read only file system

spartakus333

New Member
Apr 26, 2016
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I migrated to 4.2
but when trying to get my old VMs working in the new environement no way !!
here's an example I 've :
vm1-disk.vmdk (is a vmdk disk in an old proxmox 3 server) that I want to get it work in proxmox 4.2 in a VM with id 100.

I tried :

1- to copy vm1-disk.vmdk to [local-storage]newvm-disk.vmdk under /var/lib/vz/images/100/
I tried the cache modes (write through and write back)
=> result the VM freezes and when entering a debug mode I 'll get "read only file system" each time I create a file
I also tried converting the vm1-disk.vmdk to qcow2 and row formats, no way the same result !!

2- created a new disk under [ZFZ-STORAGE].vm-100-disk1 and cloned the old vm1-disk.vmdk to the new
disk with clonezilla (device to device)
=> result exactly the same

3- created a vzdump backup in the old server and restored it in the new one
=> the VM booted correctly... but I 've just done a reboot and it freezes again and I got the same error
read only file system !!

The new interface in 4.2 is very cool but let's get the main functions working ...:)

Thanks a lot !
 

wolfgang

Proxmox Staff Member
Oct 1, 2014
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103
Hi,

it is general no good idea to use vmdk, it is only for compatibly.
So try backup and restore to an raw image.

What is the OS of this machine?
 

spartakus333

New Member
Apr 26, 2016
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Hi thanks a lot for your reply
I did the following

1- converted my original vmdk file to the row format with the follwing command

Code:
qemu-img convert -f vmdk vm-100-disk-1.vmdk -O qcow2 vm-100-disk-1.raw

2- did the backup of my vm on [proxmox3-node1]

3- restored the backup on [proxmox4.2-node1]

4- started the restored vm
I got the following error:
Code:
kvm: -drive file=/var/lib/vz/images/105/vm-105-disk-1.raw,if=none,id=drive-virtio0,format=raw,cache=none,aio=native,detect-zeroes=on: file system may not support O_DIRECT

5- I fixed that error by changing the disk cache mode from "no cache" to "write through"

6- restarted the restored vm again
result
- the vm started
- but the disk is still accessible in read only file system

Note : the os of the hosted vm is ubuntu 12.04

Thanks a lot for your help
 

wolfgang

Proxmox Staff Member
Oct 1, 2014
6,496
493
103
Could it be that your rootfs is on ZFS.

If so please use zfs pool plugin.
 
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vkhera

Member
Feb 24, 2015
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18
Maryland, USA
Hi thanks a lot for your reply
I did the following

1- converted my original vmdk file to the row format with the follwing command

Code:
qemu-img convert -f vmdk vm-100-disk-1.vmdk -O qcow2 vm-100-disk-1.raw

qcow2 format you wrote is not "raw". Rename your image file to .qcow2 and tell KVM that it is qcow2 format, not raw format.
 

spartakus333

New Member
Apr 26, 2016
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wolfgang you're the ONE !

as you said, I used the zfs plugin and did the following:
1- created a new file system using the command
Code:
 zfs create rpool/zfsdisks
2- added a new storage:
storage (Datacenter -> [Storage] -> Add, choose "ZFS", called "zfsvols", as "ZFS Pool" choose "rpool/zfsdisks"
3- when importing my old VM I choosed "zfsvols" as storage. in which the new disk will be created

And magic ! When I started my imported VM every thing turned to the normal
and no more this horrible message of "Read only file system" ! :)

Just a last few things:

1- did I a mistake when I installed poxmox that way (I choosed zfs+raid0)
here's what I have for the command "zfs list" ?

Code:
root@node2:~# zfs list
NAME  USED  AVAIL  REFER  MOUNTPOINT
rpool  414G  485G  96K  /rpool
rpool/ROOT  10.1G  485G  96K  /rpool/ROOT
rpool/ROOT/pve-1  10.1G  485G  10.1G  /
rpool/data  297G  485G  96K  /rpool/data
rpool/data/vm-100-disk-1  66.0G  550G  1.09G  -

2- did this has influence on the performance as I noticed that the FSYNCS decreased a lot ?
Code:
root@node2:~# pveperf /rpool/zfsdisks
CPU BOGOMIPS:  24741.80
REGEX/SECOND:  2705815
HD SIZE:  485.33 GB (rpool/zfsdisks)
FSYNCS/SECOND:  218.32


Again thanks very much for your help "wolfgang"
and to all the PROXMOX dev team and community
 
Last edited:

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