[pve-devel] Error between PVE and LVM

[Alexandre DERUMIER]

So,

>>shell# lvs 
>>LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert 
>>vm-100-disk-1 drbdvg2 -wi------ 30.00g 

This value correctly change after resize ?



the resize code is here:

we first extend the lvm disk, then we tell to qemu the new disk.

(What kind of disk do you use in your guest ? virtio ? scsi ? ide ?)




/usr/share/perl5/PVE/QemuServer.pm


sub qemu_block_resize {
    my ($vmid, $deviceid, $storecfg, $volid, $size) = @_;

    my $running = check_running($vmid);

    return if !PVE::Storage::volume_resize($storecfg, $volid, $size, $running);

    return if !$running;

    vm_mon_cmd($vmid, "block_resize", device => $deviceid, size => int($size));

}


/usr/share/perl5/PVE/Storage/LVMPlugin.pm 

sub volume_resize {
    my ($class, $scfg, $storeid, $volname, $size, $running) = @_;

    $size = ($size/1024/1024) . "M";

    my $path = $class->path($scfg, $volname);
    my $cmd = ['/sbin/lvextend', '-L', $size, $path];
    run_command($cmd, errmsg => "error resizing volume '$path'");

    return 1;
}

----- Mail original ----- 

De: "Cesar Peschiera" <brain at click.com.py> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Jeudi 27 Novembre 2014 09:11:29 
Objet: Re: [pve-devel] Error between PVE and LVM 

Hi Alexandre 

Thanks for your attention, here my answers and suggestions about of the 
problem of your customer: 

>We have made no change since resize feature has been implemented. 
>Can you describe a little bit more the problem on the guest side ? 
>do you see disk size increase with parted/fdisk ? 
I see the new size (vm-100-disk-1) of the logical volume by CLI, but it 
isn't reflected into the VM. 
In my case DRBD is in a upper layer to the LV, but the concept of LVM is 
applicable for any Logical Volume in any kind of block device that Linux can 
recognise. 
shell# lvs 
LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert 
vm-100-disk-1 drbdvg2 -wi------ 30.00g 
data pve -wi-ao--- 143.50g 
root pve -wi-ao--- 20.00g 
swap pve -wi-ao--- 20.00g 

>I have add a customer during a previous training session, which have 
>problem with raw lvm disk in vms, 
I don't have problems with the VMs (LVM or raw image file), only with the 
LVM resize by CLI. 

>because of proxmox host scanning all lvm disks on the host side. (Don't 
>remember if it's have impact on resize). 
It don't have impact on resize, and it is necessary for that LVM can manage 
the changes online included (VM and host), that it is my case. 
Moreover, for my DRBD resources, i use this filter on the lvm.conf file for 
avoid scanning all lvm disks: 

filter = [ "r|/dev/sdb1|", "r|/dev/sdc1|", "r|/dev/sdd1|", "r|/dev/sde1|", 
"r|/dev/disk/|", "r|/dev/block/|", "a/.*/" ] 
Where: 
a=accept (include) , and 
r=reject (exclude) the scans to speed startup. 

>We have need to add a filter in lvm.conf on the host, to exclude scan of 
>vms lvm disk. 
Sure, i use the CLI 

An additional note of IBM: 
In the best practices, LVM as block device is the mode more fast for get the 
better performance in reads and writes of disks. 

Official Web page of IBM in "Best practice: Use block devices for VM 
storage": 
http://www-01.ibm.com/support/knowledgecenter/linuxonibm/liaat/liaatbpblock.htm 

And finally, my question: 
Can be corrected my problem? 

Best regards 
Cesar 

----- Original Message ----- 
From: "Alexandre DERUMIER" <aderumier at odiso.com> 
To: "Cesar Peschiera" <brain at click.com.py> 
Cc: <pve-devel at pve.proxmox.com> 
Sent: Thursday, November 27, 2014 3:47 AM 
Subject: Re: [pve-devel] Error between PVE and LVM 


Hi, 

>>In previous versions of PVE, this task was possible do it with much 
>>easily. 

We have made no change since resize feature has been implemented. 
Can you describe a little bit more the problem on the guest side ? 
do you see disk size increase with parted/fdisk ? 

Do you use raw lvm disk in your vms ? or partitions on top of lvm ? 
I have the LVM partition, and the image of the virtual disk isn't on a file 
system (as raw, qcow2, or any other kind of file format), so my image disk 
is a LVM as block device. 

I have add a customer during a previous training session, which have problem 
with raw lvm disk in vms, 

because of proxmox host scanning all lvm disks on the host side. (Don't 
remember if it's have impact on resize). 

We have need to add a filter in lvm.conf on the host, to exclude scan of vms 
lvm disk. 

----- Mail original ----- 

De: "Cesar Peschiera" <brain at click.com.py> 
À: pve-devel at pve.proxmox.com 
Envoyé: Jeudi 27 Novembre 2014 07:15:19 
Objet: [pve-devel] Error between PVE and LVM 

Hi to the PVE team. 

I found a problem between PVE and LVM. 

Considering that if it is used LVM as block device for the virtual disks of 
the VMs, Linux give us a great comfort, but the problem is that if I in 
"online mode" enlarge a Physical Volume and after enlarge a Logical Volume 
by CLI, in PVE, the VM can not see the new free hard disk space without 
partition. 

In previous versions of PVE, this task was possible do it with much easily. 

Moreover, i think that this feature is very util, due to that in the actual 
condition, it force me to power off the VM and start it again, so that being 
a server (talking about of the VM) that is in a production environment, only 
can I do it outside of working hours. 

So i would like to ask if the PVE team have interest in correcting this 
problem. 

Best regards 
Cesar 

_______________________________________________ 
pve-devel mailing list 
pve-devel at pve.proxmox.com 
http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel