When proxmox makes a backup, it takes more resources and the website on VM goes down because of resource lack

Aug 23, 2023
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When proxmox makes a backup, it takes more resources and the website on VM goes down of resource lack.
I have proxmox on the host and backups are going to proxmox backup server.
Any suggestions?
regards
 
When proxmox makes a backup, it takes more resources and the website on VM goes down of resource lack.
I have proxmox on the host and backups are going to proxmox backup server.
Any suggestions?
regards
Hi,
please describle in more details what resources are the bottleneck? Do you run into IO issues, memory issues or CPU limits? What services are running inside the VM? How fast is the connection to the PBS host?

Please share also your VM config qm config <VMID> and your pveversion -v.
 
RAM and CPU goes up.
Regards

pveversion -v:
proxmox-ve: 7.3-1 (running kernel: 5.15.74-1-pve)
pve-manager: 7.3-3 (running version: 7.3-3/c3928077)
pve-kernel-5.15: 7.2-14
pve-kernel-helper: 7.2-14
pve-kernel-5.15.74-1-pve: 5.15.74-1
ceph-fuse: 15.2.17-pve1
corosync: 3.1.7-pve1
criu: 3.15-1+pve-1
glusterfs-client: 9.2-1
ifupdown2: 3.1.0-1+pmx3
ksm-control-daemon: 1.4-1
libjs-extjs: 7.0.0-1
libknet1: 1.24-pve2
libproxmox-acme-perl: 1.4.2
libproxmox-backup-qemu0: 1.3.1-1
libpve-access-control: 7.2-5
libpve-apiclient-perl: 3.2-1
libpve-common-perl: 7.2-8
libpve-guest-common-perl: 4.2-3
libpve-http-server-perl: 4.1-5
libpve-storage-perl: 7.2-12
libspice-server1: 0.14.3-2.1
lvm2: 2.03.11-2.1
lxc-pve: 5.0.0-3
lxcfs: 4.0.12-pve1
novnc-pve: 1.3.0-3
proxmox-backup-client: 2.2.7-1
proxmox-backup-file-restore: 2.2.7-1
proxmox-mini-journalreader: 1.3-1
proxmox-widget-toolkit: 3.5.3
pve-cluster: 7.3-1
pve-container: 4.4-2
pve-docs: 7.3-1
pve-edk2-firmware: 3.20220526-1
pve-firewall: 4.2-7
pve-firmware: 3.5-6
pve-ha-manager: 3.5.1
pve-i18n: 2.8-1
pve-qemu-kvm: 7.1.0-4
pve-xtermjs: 4.16.0-1
qemu-server: 7.3-1
smartmontools: 7.2-pve3
spiceterm: 3.2-2
swtpm: 0.8.0~bpo11+2
vncterm: 1.7-1
zfsutils-linux: 2.1.6-pve1

Config (but it is happening for la VMs):
agent: 1
boot: order=scsi0;ide2;net0
cores: 2
ide2: local:iso/ubuntu-22.04.2-live-server-amd64.iso,media=cdrom,size=1929660K
memory: 10240
meta: creation-qemu=7.1.0,ctime=1680006393
name: LazyHouse
net0: virtio=00:50:56:00:38:32,bridge=vmbr0,firewall=1
numa: 0
onboot: 1
ostype: l26
scsi0: local-lvm:vm-101-disk-0,discard=on,iothread=1,size=400G
scsihw: virtio-scsi-single
smbios1: uuid=f5dd4041-3dcd-490f-9313-f47d52396e6c
sockets: 1
vmgenid: 8c7de333-57ad-48e3-9999-06dede38bbde
 
Thanks for the outputs, it seems you still run a rather old version of Proxmox VE and missing out on a lot of bug fixes and security pathes. I would suggest to upgrade to at least the latest version 7.4 or even to 8.0. See [0] for detailed upgrade steps from 7.x to 8.0.

Regarding the issue, please attach the full backup job task log and the output of cat /proc/pressure/io, cat /proc/pressure/cpu and cat /proc/pressure/memory after the VM backup was running.

In order to help, you might also want to share more details about the hardware and resources the host has at its disposal.
Further, also check the systemd journal from within the VM for hints on what is limiting the VM. journalctl -b -r gives you a paginated view of the journal in reverse order.

[0] https://pve.proxmox.com/wiki/Upgrade_from_7_to_8
 
Do you have a fast and reliable connection to the PBS host? What latency and bandwidth do you expect? Can you check by tools such as fio and perform a proxmox-backup-client benchmark --repository <string> giving your repository as target. See also https://pbs.proxmox.com/docs/backup-client.html#benchmarking

Note that it is a known limitation that backups with a slow connection to the remote PBS host and high write load in the VM might run into such issues. This is inherit to the way the backups are performed. https://bugzilla.proxmox.com/show_bug.cgi?id=3231#c4

To avoid such issues, performing a Backup to a local PBS instance and move the backups by sync jobs to the remote location can be done. See https://pbs.proxmox.com/docs/managing-remotes.html#sync-jobs
 

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