Slow vzdump backups to NFS

[Richard Leishman]

Hello

I am trying to backup virtual machines (LVM over iSCSi storage) in online mode but they are very slow. I have tested storage, network and cpu performance but can not work out what it is.

I have a dedicated machine with 22x 300GB SAS disks in raid 10 when I test with DD (if=/dev/zero) over NFS from a Proxmox node, I am achieving roughly 450-500MB/s write speeds.

When testing the speed of one of our storage servers using DD (of=/dev/null), I am achieving roughly 300MB/s.

When I use vzdump (no bwlimit/ionice 7) to backup using no compression (raw) I am achieving roughly 90MB/s...
With lzo compression I am achieving roughly 18-20MB/s.

The nodes are Intel Xeon 24 cores with 64GB ram with roughly 10% cpu usage and 30gb ram free.

Some may see 90MB/s as quite good but not when you are trying to backup 4TB of data each night.

Are there other/better backup methods?

Thank you in advance

 

[blackpaw]

/etc/vzdump.conf has some settings for bandwidth limiting - maybe they are set?

 

[wolfgang]

Hi,

you try to backup a VM from a LVM over iSCSi storage.
What is the target storage?

I have a dedicated machine with 22x 300GB SAS disks in raid 10 when I test with DD (if=/dev/zero) over NFS from a Proxmox node, I am achieving roughly 450-500MB/s write speeds.

is this the write test to the backup storage?
If yes please retry with random data.