[Qemu-devel] drive-mirroring to nbd is failing with multiple parallel jobs (qemu 2.9 -> 2.11)

[Alexandre DERUMIER]

Hi,

I currently have failing mirroring jobs to nbd, when multiple jobs are running 
in parallel.


step to reproduce, with 2 disks:


1) launch mirroring job of first disk to remote target nbd.(to qemu running 
target)
2) wait until is reach  ready = 1 , do not complete
3) launch mirroring job of second disk to remote target nbd(to same qemu 
running target)

-> mirroring job of second disk is currently running (ready=0), first disk is 
still at ready=1 and still mirroring new write coming.


then, after some time, mainly if no new write are coming to first disk (around 
30-40s), the first job is crashing with input/output error.



Note that I don't have network problem, or disk problem, I'm able to mirror 
both disk individually.


Another similar bug report on proxmox bugzilla:

https://bugzilla.proxmox.com/show_bug.cgi?id=1664


Maybe related to this :
https://lists.gnu.org/archive/html/qemu-devel/2017-11/msg03086.html
?


I don't remember to have the problem with qemu 2.7, but I'm able to reproduce 
with qemu 2.9 && qemu 2.11.


Best Regards,

Alexandre