<![CDATA[Live Migration Very Slow]]>Xen Orchestra, commit 32228
Master, commit 32228

Hi,

I have a two host pool that uses shared storage for all VMs. When I try to perform a VM migrate, using either the management network (1Gbs) or the 20Gbps NFS network, the live migration can take a long time (see example below):
91eb5e25-fd80-460e-9462-7b1e2539108c-image.png
d6df8e38-5ee1-48da-973b-1551546accf1-image.png

I thought when the VM is using the shared storage of a pool, then moving VMs should be very fast as there is no disk data that needs to be moved other than the VM ram.

Both hosts Control Domains have assigned 16 GB of memory.

Source host shows the following:

185a3135-4fcd-4d86-b44b-f80aaf515875-image.png

71dc9539-98af-4662-bf70-bcec58c82d60-image.png

240553e9-4e47-453a-90e1-7a8db02b9b61-image.png

Target host shows the following:

d1bd33bd-8fb4-4716-a259-cdbd93d5f9bb-image.png

5e649d7b-30dd-436e-9bc8-b22a72da3e22-image.png

68060277-1cb7-4a59-a184-9848c7ed9e42-image.png

Any recommendations on what could be causing the slow live migration if the VM resides on the pool shared storage?

Also, our XOCE VM resides on a different pool than the pool I'm performing the live migration. Wasn't sure if that matters or not.

Thank You,

SW

]]>https://xcp-ng.org/forum/topic/9506/live-migration-very-slowRSS for NodeMon, 15 Jun 2026 09:00:39 GMTWed, 14 Aug 2024 01:31:28 GMT60<![CDATA[Reply to Live Migration Very Slow on Thu, 20 Mar 2025 14:25:55 GMT]]>@Forza There are various topics touching on how SMAPIv1 is a bottleneck here, eg: https://xcp-ng.org/forum/topic/9389/backup-migration-performance/8 - that's probably not the best example as it is also more on backups than migration!

]]>https://xcp-ng.org/forum/post/90968https://xcp-ng.org/forum/post/90968Thu, 20 Mar 2025 14:25:55 GMT<![CDATA[Reply to Live Migration Very Slow on Wed, 19 Mar 2025 20:23:51 GMT]]>@olivierlambert aha, I misinderstood. Should I open another topic or perhaps a support ticket?

]]>https://xcp-ng.org/forum/post/90965https://xcp-ng.org/forum/post/90965Wed, 19 Mar 2025 20:23:51 GMT<![CDATA[Reply to Live Migration Very Slow on Wed, 19 Mar 2025 18:09:13 GMT]]>@Forza Sorry but that's unrelated in this topic. OP talks about live migration with a shared SR. Storage migration is really another topic.

]]>https://xcp-ng.org/forum/post/90954https://xcp-ng.org/forum/post/90954Wed, 19 Mar 2025 18:09:13 GMT<![CDATA[Reply to Live Migration Very Slow on Wed, 19 Mar 2025 13:49:38 GMT]]>Hi, sorry for revisiting an older topic, but we have the same issue with slow VM migration. We changed from 2x1G to 2x10G network, but the migration performance from one host's local SR to another host local SR is not much improved.

9eb4913a-3ed6-4376-b653-23090e323bd6-image.png

611ce830-d3cc-4153-89b9-9d4e1c92d6b4-image.png

Using XCP-ng 8.2.1 with up-to-date patches. Local storage on both hosts is SSD RAID1, ext4.

It would be very good if we could improve this situation. Currently we are seeing only 5% network utilisation.

]]>https://xcp-ng.org/forum/post/90932https://xcp-ng.org/forum/post/90932Wed, 19 Mar 2025 13:49:38 GMT<![CDATA[Reply to Live Migration Very Slow on Wed, 27 Nov 2024 10:13:37 GMT]]>Live migration speed per VM isn't really fast due how memory is split is very small 4k blocks. However, it scales OK if you migrate multiple VMs at once. Obviously, this is not a solution in your case where you need faster migration per VM. This is a topic we'd like to work on in the following months 🙂

]]>https://xcp-ng.org/forum/post/86297https://xcp-ng.org/forum/post/86297Wed, 27 Nov 2024 10:13:37 GMT<![CDATA[Reply to Live Migration Very Slow on Tue, 26 Nov 2024 22:22:49 GMT]]>@stevewest15 that is a shame! Thanks for sharing!

]]>https://xcp-ng.org/forum/post/86286https://xcp-ng.org/forum/post/86286Tue, 26 Nov 2024 22:22:49 GMT<![CDATA[Reply to Live Migration Very Slow on Tue, 26 Nov 2024 16:09:21 GMT]]>@andrewperry I couldn't get the live migration to work on large VMs. To move large VMs, I ended up taking a snapshot of the VM and then creating a new VM from that snapshot. It's not ideal but had to do that as we needed to retire some old servers and I couldn't get the live migration to work w/ large VMs.

]]>https://xcp-ng.org/forum/post/86262https://xcp-ng.org/forum/post/86262Tue, 26 Nov 2024 16:09:21 GMT<![CDATA[Reply to Live Migration Very Slow on Tue, 26 Nov 2024 08:48:10 GMT]]>Were you able to work it out? I have a 32GB RAM domU that keeps failing migration between nodes unfortunately!

]]>https://xcp-ng.org/forum/post/86215https://xcp-ng.org/forum/post/86215Tue, 26 Nov 2024 08:48:10 GMT