Backup of a specific VM cause problems (broken pipe, no config), even node crashes

[fips]

Hey!
I have a 3 node setup, some CT, some VMs. Disks all stored on a 10g LVM iSCSI attached NAS.
Backup goes to a NFS with an attached SSD.
Everything works nice am well, except 1 VM.
It is a simple debian VM where I receive data via rsync.
So in the past the bootdisk of that VM was about 40 GB, now I had to increase it to 150GB and the problems started:
When vzdump start a scheduled backup, sometimes it throw "vma_queue_write: write error - Broken pipe" and its not saved.
Last night, it gave me "
VM 201 qmp command failed - unable to find configuration file for VM 201 - no such machine
" but then even the node crashed... very annoying!
The problem started since I increased the VM size, but I have bigger VM Disks too.
They can be backuped the same way without problems.

The problematic VM has just 1 cpu and 1 GB, Cache ist set to default.
Can that be the reason?

 

[manu]

the vma_queue_write may mean that the NFS server was not available when the backup started
try a manual backup, after remocing the backup lock if needed ( see the qm unlock command in the qm manpage)

 

[fips]

Well this is what I am doing and it works without problems.
But I don't understand why it happens to only that specific VM.