Simultaneous VMs backups between two nodes PVE Cluster and bwlimit

cesarpk

Active Member
Mar 31, 2012
770
3
38
Hi to all

Please, anyone can help me with this question:

My scenario:
- Two (2) Nodes with: PVE 2.2 (ISO installer) + PVE cluster + NFS server (obviously in each one)
- Three (3) KVM VMs with diferents Sist. Operat. and services in each PVE Host (Total = 6 VMs)
- Servers are DELL with HDD SAS and NICs broadcom of 1 Gb/s
- At night we have in low activity or no activity in the company

Three questions:

1- Can I schedule the tasks of backups between nodes simultaneously at midnight?, that is to say:
At 00 Hrs. PVE Node A will make VMs Backups on NFS share into PVE Node B, and simultaneously
At 00 Hrs. PVE Node B will make VMs Backups on NFS share into PVE Node A
(I don't know if this is a problem for LVM into the PVE Nodes, I'm not sure how it works LVM)

2- About bwlimit on vzdump configuration: What is the maximum speed recommended for use with 1 Gb. NIC without lost the PVE cluster comunication?

3- And if I do local backup, is necessary modify the feature bwlimit of vzdump configuration file for obtain more speed in the backup?. (If the answer is yes, I believe that it would be better to put almost the speed limit disk write in this case).

I will be very grateful to anyone who can disciparme these doubts.

Best regards
Cesar
 

dietmar

Proxmox Staff Member
Staff member
Apr 28, 2005
17,042
474
103
Austria
www.proxmox.com
1- Can I schedule the tasks of backups between nodes simultaneously at midnight?, that is to say:

yes, you can do that. But traffic on the network can be high - use bwlimit.


2- About bwlimit on vzdump configuration: What is the maximum speed recommended for use with 1 Gb. NIC without lost the PVE cluster comunication?

Try out - depends on other NFS activity (it is better to use separate network for cluster communication).

3- And if I do local backup, is necessary modify the feature bwlimit of vzdump configuration file for obtain more speed in the backup?.

no (default is unlimited, with low io prio)
 

cesarpk

Active Member
Mar 31, 2012
770
3
38
yes, you can do that. But traffic on the network can be high - use bwlimit.
Try out - depends on other NFS activity (it is better to use separate network for cluster communication).
no (default is unlimited, with low io prio)

Hi Dietmar and thank's for your prompt response.
please let me to do two questions:

Important notes:
1- I want high traffic on the network for do quick backups ("By node" I have 3 VMs, then I have +/- 350 Gbytes of data for do backup), backups are necessary for both nodes, and all backups should finish before dawn.

2- I don't have extra NICs free for use

Questions
1- If by default vzdump have the feature "bwlimit" unlimited, and I don't want to modify this option, what will happen with PVE Cluster if I don't configure this feature and do backup on both PVE Cluster with NFS shared? (If of this manner don't will happen problems, then is a excelent option for my purpose)
And the question more important now for me:
2- How much bandwidth on the network is the minimum necessary for proper functioning of PVE Cluster?

I will be very grateful Dietmar (or anyone) if you can dissipate these doubts.

Best regards
Cesar
 

cesarpk

Active Member
Mar 31, 2012
770
3
38
yes, you can do that. But traffic on the network can be high - use bwlimit.

Dietmar or anyone can help me?

snif, snif, snif :( , not working properly - backup snapshot
At 00 Hrs. PVE Node A make VMs Backups on NFS share into PVE Node B, but
At 00 Hrs. PVE Node B not make backups on NFS share into PVE Node A.

This is the error message (Node B):

INFO: starting new backup job: vzdump 105 106 107 --quiet 1 --mailto x@y.com --mode snapshot --compress gzip --storage Backups_en_kvm3 --node kvm4
INFO: Starting Backup of VM 105 (qemu)
INFO: status = running
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: Logical volume "vzsnap-kvm4-0" created
INFO: creating archive '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-105-2012_11_16-00_00_02.tar.gz'
INFO: adding '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-105-2012_11_16-00_00_02.tmp/qemu-server.conf' to archive ('qemu-server.conf')
INFO: adding '/mnt/vzsnap0/images/105/vm-105-disk-1.raw' to archive ('vm-disk-ide0.raw')
INFO: ERROR: incomplete read detected
ERROR: Backup of VM 105 failed - command '/usr/lib/qemu-server/vmtar '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-105-2012_11_16-00_00_02.tmp/qemu-server.conf' 'qemu-server.conf' '/mnt/vzsnap0/images/105/vm-105-disk-1.raw' 'vm-disk-ide0.raw'|gzip >/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-105-2012_11_16-00_00_02.tar.dat' failed: exit code 255
INFO: Starting Backup of VM 106 (qemu)
INFO: status = running
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: Logical volume "vzsnap-kvm4-0" created
INFO: creating archive '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-106-2012_11_16-00_01_41.tar.gz'
INFO: adding '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-106-2012_11_16-00_01_41.tmp/qemu-server.conf' to archive ('qemu-server.conf')
INFO: adding '/mnt/vzsnap0/images/106/vm-106-disk-1.raw' to archive ('vm-disk-virtio0.raw')
INFO: ERROR: incomplete read detected
ERROR: Backup of VM 106 failed - command '/usr/lib/qemu-server/vmtar '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-106-2012_11_16-00_01_41.tmp/qemu-server.conf' 'qemu-server.conf' '/mnt/vzsnap0/images/106/vm-106-disk-1.raw' 'vm-disk-virtio0.raw'|gzip >/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-106-2012_11_16-00_01_41.tar.dat' failed: exit code 255
INFO: Starting Backup of VM 107 (qemu)
INFO: status = running
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: Logical volume "vzsnap-kvm4-0" created
INFO: creating archive '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-107-2012_11_16-00_02_29.tar.gz'
INFO: adding '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-107-2012_11_16-00_02_29.tmp/qemu-server.conf' to archive ('qemu-server.conf')
INFO: adding '/mnt/vzsnap0/images/107/vm-107-disk-1.raw' to archive ('vm-disk-virtio0.raw')
INFO: ERROR: incomplete read detected
ERROR: Backup of VM 107 failed - command '/usr/lib/qemu-server/vmtar '/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-107-2012_11_16-00_02_29.tmp/qemu-server.conf' 'qemu-server.conf' '/mnt/vzsnap0/images/107/vm-107-disk-1.raw' 'vm-disk-virtio0.raw'|gzip >/mnt/pve/Backups_en_kvm3/dump/vzdump-qemu-107-2012_11_16-00_02_29.tar.dat' failed: exit code 255
INFO: Backup job finished with errors
TASK ERROR: job errors

Best regards
Cesar
 

cesarpk

Active Member
Mar 31, 2012
770
3
38
Your LVM snapshot runs out of space - please increase snapshot size.

Thank you Dietmar for your prompt response

Do you can give me the formula for use on any case?

I will be very grateful Dietmar

Best regards
Cesar
 

cesarpk

Active Member
Mar 31, 2012
770
3
38
There is no easy 'formula' for that, because required snapshot space depends on many factors (activity inside the VM). Simply duplicator size an test again.

I understand you Dietmar, and if we assume that there is no activity inside the VM, Do you can give me the formula? - just pretend to have a rough idea and that i not feel lost in the space for futures changes
Thank you very much anyway

Best regards
Cesar
 
Last edited:

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