Hello stackers,

I'm reaching out to the community to understand how you manage migrations of memory-intensive instances.

We are running RHOSP 17.1 (based on Wallaby) and have faced several issues when live-migrating instances running on compute nodes to do maintenance work.

For several memory-intensive instances, the process just never completes properly and ends in error after hours waiting. During the migration, we can see in nova-computes.log of destination compute node that the migration never truly migrates the memory, whenever the reported percentage of memory remaining is close to 0%, it ends up to go back to high percentage again.

 

By looking at the migration UUID, we saw that the memory processed bytes is way higher than the memory total bytes [1].

We played with several `live_migration` options in nova.conf but to no end.

Has anyone faced the same issue ?

And most importantly, how do you handle the migration of your memory-intensive workload ?

 

Regards,

Timothé

[1]. 

$ openstack server migration show 328af6d9-9c9d-4671-a8f9-2c0d3df32b93 e2cda681-e25c-4aca-813c-3641bc6164c9 

+------------------------+------------------------------------------------------------------+

| Field                  | Value                                                            |

+------------------------+------------------------------------------------------------------+

| ID                     | 13231                                                            |

| Server UUID            | 328af6d9-9c9d-4671-a8f9-2c0d3df32b93                             |

| Status                 | running                                                          |

| Source Compute         | compute02                        |

| Source Node            | compute02                        |

| Dest Compute           | compute01                        |

| Dest Host              | None                                                             |

| Dest Node              | compute01                       |

| Memory Total Bytes     | 137448202240                                                     |

| Memory Processed Bytes | 5300502117730                                                    |

| Memory Remaining Bytes | 52182556672                                                      |

| Disk Total Bytes       | 0                                                                |

| Disk Processed Bytes   | 0                                                                |

| Disk Remaining Bytes   | 0                                                                |

| Created At             | 2026-03-24T10:49:15.000000                                       |

| Updated At             | 2026-03-24T13:14:32.000000                                       |

| UUID                   | e2cda681-e25c-4aca-813c-3641bc6164c9                             |

| User ID                | cc4367e52cce828fa3e378f29ed6df553c2dd99e9a4b33f1835fee719d592c91 |

| Project ID             | 0382d25c311149fabd7bea0d6fa3ac37                                 |

+------------------------+------------------------------------------------------------------+