XCP-ng VM transfer speed on shared SR

Computer Hardware & Server Infrastructure Builds
1

2 pools with 3 hosts each (XCP-ng 8.2.1). Old pool with 1G NICs, new pool with 10G NICs. Shared SRs on both pools (lvmohba), multipathing enabled. Live migration of VM (2GB RAM, 30GB HDD) inside pool takes similar times (47s on 1G vs 39s on 10G). I was hoping to see bigger difference moving to 10G. Is this normal?

My regards!

2

There is a lot of factors most of which is that the VM transfer is bound by CPU and by the speed of the storage on the source and destination.

3

I thought that only VMs RAM is transfered from one host to another in case of shared SR? My VM is located on shared SR…

4

I read that as you were moving the system between pools. If the storage is not moving then it’s mostly bound by CPU.

5

I think XCP-NG reserves some of the reasources for other functions, I’ve never seen a migration on my system go faster than about 2-3gbps between hosts in the same pool.

6

All clear now. So CPU and host storage speed dependant. I have done testing with SSDs instead HDDs on hosts and got just couple of seconds better results. Thank you for explaining.

7

I should also mention that when it is moving 2 VMs, I get a little faster migration, I think I saw 4.5gbps on day when I was doing a rolling pool upgrade.

And that said, I have never had an issue with slow performance from one of my servers when I’ve needed to do these things during a normal workday, so some performance must be held in reserve for the server to do real work (unless you have a dedicated network for things like migrations, which I don’t).