How it works the NBD? I don't see improvements
-
Hi all,
sorry I'm not expert and I would lik to ask you clarifications regarding the network protocol NBD.
I'm using the last version of Orchestra (update today) from source, and I'm testing it with Xen Server 8.2.I did a full backup of one VM and it took 27 Min.
• Duration: 27 minutes
• Size: 99.87 GiB
• Speed: 63.32 MiB/sThan I did it again with NBD (4 connection) and the result is the same.
• Duration: 27 minutes
• Size: 99.87 GiB
• Speed: 63.25 MiB/sI can confirm the NBD because now I see also the text (Transfer data using NBD).
CBT I can't test for the moment because the XenServer has only the standard license.
Can someone explain me a bit more in detail how it works?
Many thanks in advance
BR
Marco -
It's sounds very very similar (maybe too similar), double check the history of CPU usage on your dom0/host with and without it. VHD export is like 20/25% CPU vs 5% with NBD. It could be also another bottleneck somewhere else, as it's a stream, it will max the speed of the slowest element in the chain.
-
@olivierlambert Thanks a lot for the quick reply. I checked with the command "xentop" on my server.
When I run the Backup, with or without the NDB the CPU increase from 50% to 120-160%.
Now I'm testing one backup per time, and what I see is that in both scenarios the transfer rate is: 110.18 MiB/s so almost the 1 GB. SO I think the bottleneck is the network. I mean on the Hypervisor I have 2 GB because I have the LACP, but the Virtual NIC of the XO is 1G.
Did I unterstand correctly?
Thanks
BR
Marco -
You can just compare the stats in XO in the host view/stats and CPU graph.
-
@olivierlambert below you see two bacups on the stat, The first is with NDB and the second without.
-
It's hard to see anything due to the high number of CPUs. It sounds really really similar though, I'm under the impression both are using NBD
@florent any idea? -
@olivierlambert If you want me to check anything else, just tell me and I will test for you.
Many Thanks
BR
Marco
