[pve-devel] [PATCH] Qemu Guest IOPS Graphing

[Dietmar Maurer]

> I am still trying to come up with an alternative method that results in 
> no blip on the statistics, but possibly someone has on the list might 
> have a suggestion? I ask as how else are changes going to be made to the 
> RRD tables if slight data loss and some broken graphs (due to missing 
> tables on mixed version clusters) isn't an option?

This is really not easy, and I thought about the following:

- do not touch existing message format
- do not touch existing rrd images

instead, send an additional message in pvestatd:

	PVE::Cluster::broadcast_rrd("pve2.3-vm/$vmid", $data); # current code
 	PVE::Cluster::broadcast_rrd("pve4.0-vm/$vmid", $modified_data); # new message
        
Inside pmxcfs, we simply write pve4.0-vm data into another rrd file (and
ignore pve2.3-vm messages.

I guess that would avoid data loss (but old data is in other file).