1 VM with 4 virtual disks?

[ericmachine]

Hi everyone,

Someone told me that instead of having

1 VM with Ubuntu LVM inside

He recomends to have this instead as it will be more suitable for recovery & expansion.

No LVM at OS level

1 VM but breaks down into 4 virtual disks.

/home -> 1 virtual disk
/var -> 1 virtual disk
and 2 more paths

Any idea how to do this? Plus what's the benefits of doing this?

Any help? Thanks.

 

[udo]

Hi everyone,

Someone told me that instead of having

1 VM with Ubuntu LVM inside

He recomends to have this instead as it will be more suitable for recovery & expansion.

Sorry, but that's isn't right. You can easy expand the disk with pve and after that expand the disk (lvm-storage) inside the VM. Or add another disk and use this for the same VG.

No LVM at OS level

You mean inside VM? I have many VMs with lvm - run very well.

1 VM but breaks down into 4 virtual disks.

/home -> 1 virtual disk
/var -> 1 virtual disk
and 2 more paths

Any idea how to do this? Plus what's the benefits of doing this?

Any help? Thanks.

I see the only benefit in one less layer between hardware and VM-OS - but with fast raids this isn't realy an problem.
You are much more flexible with lvm!

Udo

 

[ericmachine]

Sorry, but that's isn't right. You can easy expand the disk with pve and after that expand the disk (lvm-storage) inside the VM. Or add another disk and use this for the same VG.

You mean inside VM? I have many VMs with lvm - run very well.

I see the only benefit in one less layer between hardware and VM-OS - but with fast raids this isn't realy an problem.
You are much more flexible with lvm!

Udo

Thanks Udo again.

Few more questions.

a. When you say this You can easy expand the disk with pve and after that expand the disk (lvm-storage) inside the VM

Is this something that can be done on proxmox interface? Or do I have to do it command line?

I assume this.

Now I have a server at proxmox v2. It has 1TB hard disks RAID 1. Say I add another 1TB hard disk with RAID 1.

Then I want to increase my HDD size for the existing VMs running in my proxmox v2.

How can I do that like you mentioned? Any tips or links which I can refer to?

b. When I say LVM, I am referring to Ubuntu 12.04 LTS LVM (during installation, I chose LVM instead of entire disk). I hope that's what you meant too and not proxmox lvm feature

c. When you say this but with fast raids this isn't realy an problem

I know RAID10 is fast. How about RAID6?

Any help? Thanks.

 

[udo]

Thanks Udo again.

Few more questions.

a. When you say this You can easy expand the disk with pve and after that expand the disk (lvm-storage) inside the VM

Is this something that can be done on proxmox interface? Or do I have to do it command line?

with the actual pve selct the harddisk and you see the point "resize disk".

Now I have a server at proxmox v2. It has 1TB hard disks RAID 1. Say I add another 1TB hard disk with RAID 1.

Then I want to increase my HDD size for the existing VMs running in my proxmox v2.

How can I do that like you mentioned? Any tips or links which I can refer to?

pve2 is outdated - do an upgrade and use the gui.
BUT - raid1 is only for safety - you don't have more space (and also not more speed). With two disk you got more space and speed with raid0 !attation - very unsecure!!

b. When I say LVM, I am referring to Ubuntu 12.04 LTS LVM (during installation, I chose LVM instead of entire disk). I hope that's what you meant too and not proxmox lvm feature

right

c. When you say this but with fast raids this isn't realy an problem

I know RAID10 is fast. How about RAID6?

Any help? Thanks.

look for benchmarks in the web about your preferred raid-controller and disks. Esp. the write-speed is not so good on raid6 (the same with raid5). And with 4 disks you have the same space with raid10 and raid6.

Udo

 

[ericmachine]

with the actual pve selct the harddisk and you see the point "resize disk".

pve2 is outdated - do an upgrade and use the gui.
BUT - raid1 is only for safety - you don't have more space (and also not more speed). With two disk you got more space and speed with raid0 !attation - very unsecure!!

right

look for benchmarks in the web about your preferred raid-controller and disks. Esp. the write-speed is not so good on raid6 (the same with raid5). And with 4 disks you have the same space with raid10 and raid6.

Udo

got it thanks so much