[pve-devel] Error between PVE and LVM
Cesar Peschiera
brain at click.com.py
Thu Nov 27 17:00:37 CET 2014
Hi Alexandre
>This value correctly change after resize ?
If, before change, the logical volume had a smaller size.
>We first extend the lvm disk, then we tell to qemu the new disk.
This process is correct when you use the GUI, but when you have space
limited in the hard disk, and you want to change some partitions by CLI,
where finally will be working with the logical volumes, is when starting the
problem due that the VM not see the change applied.
Please let me to do two suggestions:
- Maybe will be better than PVE GUI have a option that say: "resize to max
available", or something.
I guess that this first option would be very good due to that the user will
not need calculate the space available considering the space used in the
metadata of LVM.
- Moreover, in previous versions of PVE, while that I could see the
reflected changes into the VM, in the PVE GUI, when i see the size of his
hard disk, it shows his old size, then i had that remove the disk for re add
it, only of this manner i could see his new size.
>What kind of disk do you use in your guest ? virtio ? scsi ? ide ?
Virtio-block, moreover i have good references about virtio-scsi, do you know
something about virtio-scsi for use it in windows systems?
Many thanks again for your attention
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 6:35 AM
Subject: Re: [pve-devel] Error between PVE and LVM
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
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