Most stable image format raw, qcow2 or vmdk for KVM and Linux only guest

mbs

New Member
Dec 13, 2010
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Hi,

can someone please advise what is the most stable image format (raw, qcow2
or vmdk) to run KVM with Linux guest only?

I just installed PVE 1.7 with kernel 2.6.32-4-pve, but might switch back to
an older kernel and PVE release, if that affects stability in a positive way.

I want to make sure to run the most stable environment for production, even
if I miss the latest features.

Regards
 
Hi,

can someone please advise what is the most stable image format (raw, qcow2
or vmdk) to run KVM with Linux guest only?

most stable and fastest is not using a image format - use block devices directly (with LVM). if you cannot use block devices, use raw (which is also no format, its just raw).

I just installed PVE 1.7 with kernel 2.6.32-4-pve, but might switch back to
an older kernel and PVE release, if that affects stability in a positive way.

I want to make sure to run the most stable environment for production, even
if I miss the latest features.

Regards

2.6.32 is the most used and current the default kernel branch, looks long term supported.
 
Hi Tom,

based on your hints I prepared my hardware setup as follows:

Hardware Raid 1 (sda): Here I installed the Proxmox environment
Hardware Raid 5 (sdb): This disk I prepared as described in the wiki:

http://pve.proxmox.com/wiki/Storage_Model#LVM_Groups_with_Local_Backing

Creating the pysical volume:

pvcreate /dev/sdb1

Creating the volume group:

vgcreate vgsdb1 /dev/sdb1

Finally adding the new LVM group to the local storage via the web interface.


Now, when creating a new KVM machine using the newly added LVM group, only RAW can be selected as "image format".

When the machine has been created, lvdisplay shows a new logical volume.


Is that "so called" RAW actually the LVM "block device" method to be used for most stable and fastest operation describe in you first reply?

Is it correct to use VIRTIO disk type in KVM for Linux guests?

Best regards
Markus
 
Last edited:
if you use block devices directly (incl. LVM) there is no image format involved (we display 'raw') - and yes, this is the best method.

virtio is recommended for Linux guest (block and net), most modern Linux kernel includes these virtio drivers already.
 
Tom,

thank you for you fast response!

I think it is really important to start with the correct setup right from the beginning.

With that essential knowledge I will send my three-server-cluster-setup into production.

Happy Proxmoxing!
 

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