I have a three node oVirt 4.4.5 cluster running oVirt node hosts. Storage is mix of GlusterFS and NFS. Everything has been running smoothly, but the other day I noticed many VMs had invalid snapshots. I run a script to export OVA for VMs for backup purposes, exports seemed to have been fine but snapshots failed to delete at the end. I was able to manually delete the snapshots through oVirt admin GUI without any errors/warnings and the VMs have been running fine and can restart them without problems.

I thought this problem may be due to snapshot bug which is supposedly fixed in oVirt 4.4.6. I decided to start upgrading cluster to 4.4.6 and am now having a problem with VMs not being able to migrate.

When I migrate any VM (doesn't seem to matter which host to and from) the process starts but stops at 0-1%. Eventually after 15-30 minutes or more the tasks are all completed by the VM is not migrated. 

I am unable to migrate any VMs and as such I cannot place any host in maintenance mode.

I've attaching some VDSM logs from source and destination hosts, these were after initiating a migration of a single VM

I'm seeing some errors in the logs regarding the migration stalling, but not able to determine why its stalling.

2021-05-27 17:10:22,167+0000 INFO  (jsonrpc/4) [api.host] FINISH getAllVmIoTunePolicies return={'status': {'code': 0, 'message': 'Done'}, 'io_tune_policies_dict': {'f8f4e4a1-b565-4663-8962-c8804dbb86fb': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme1n1/bce04425-1d25-4489-bdab-2834a1a57db8/images/38b27cce-c744-4a12-85a3-3af07d386da2/93c1e793-f8cb-42c9-86a6-0e9ce4a6023a', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '2b87204f-f695-474a-9f08-47b85fcac366': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/f2e0c9f3-ab0d-441a-85a6-07a42e78b5a8/848f353e-6787-4e20-ab7b-0541ebd852c6', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '26332421-54a3-4afc-90e7-551a7e314c80': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/b7a785f9-307b-42af-9bbe-23cac884fe97/ed1d027e-a36a-4e6b-9207-119915044e06', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '60edbd80-dad7-4bf8-8fd1-e138413cf9f6': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/535fcb2e-ece9-4d50-86fe-bf6264d11ae1/6c01a036-8a14-46ba-a4b4-fe4f66a586a3', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdb', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/1f467fb5-5ea7-42ba-bace-f175c86791b2/cbe8327f-9b7f-442f-a650-6888bb11a674', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdd', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/c93956d5-c88d-41f9-8c38-9f5f62cc90dd/3920b46c-5fab-4b63-b47f-2fa5c6714c36', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, 'beeefe06-78a0-4e14-a932-cc8d734d542d': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/glusterSD/gluster0.grove.silverorange.com:_data__sdb/30fd0a2f-ab42-4a8a-8f0b-67242dc2d15d/images/310d8b3e-d578-418d-9802-dc0ebcea06d6/aa758c51-8478-4273-aeef-d4b374b8d6b4', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdb', 'path': '/rhev/data-center/mnt/glusterSD/gluster0.grove.silverorange.com:_data__sdb/30fd0a2f-ab42-4a8a-8f0b-67242dc2d15d/images/4072fda1-ec82-45c9-b353-91fceb13bf08/891f5982-dead-48b4-8907-caa1e309fa82', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '7e5156de-649d-4904-9092-21a699242a37': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/ca0c1208-a7aa-4ef6-a450-4a40bd4455f3/a2335199-ddd4-429b-b55d-f4d527081fd3', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}}} from=::1,35012 (api:54)
2021-05-27 17:10:31,118+0000 WARN  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration stalling: remaining (32863MiB) > lowmark (32863MiB). (migration:801)
2021-05-27 17:10:31,118+0000 INFO  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration Progress: 190.035 seconds elapsed, 1% of data processed, total data: 32864MB, processed data: 0MB, remaining data: 32863MB, transfer speed 0Mbps, zero pages: 160MB, compressed: 0MB, dirty rate: 0, memory iteration: 1 (migration:814)
2021-05-27 17:10:33,827+0000 INFO  (jsonrpc/5) [throttled] Current getAllVmStats: {'f8f4e4a1-b565-4663-8962-c8804dbb86fb': 'Up', '2b87204f-f695-474a-9f08-47b85fcac366': 'Up', '26332421-54a3-4afc-90e7-551a7e314c80': 'Up', '60edbd80-dad7-4bf8-8fd1-e138413cf9f6': 'Up', 'beeefe06-78a0-4e14-a932-cc8d734d542d': 'Up', '7e5156de-649d-4904-9092-21a699242a37': 'Migration Source'} (throttledlog:104)
2021-05-27 17:10:37,186+0000 INFO  (jsonrpc/5) [api.host] FINISH getAllVmIoTunePolicies return={'status': {'code': 0, 'message': 'Done'}, 'io_tune_policies_dict': {'f8f4e4a1-b565-4663-8962-c8804dbb86fb': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme1n1/bce04425-1d25-4489-bdab-2834a1a57db8/images/38b27cce-c744-4a12-85a3-3af07d386da2/93c1e793-f8cb-42c9-86a6-0e9ce4a6023a', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '2b87204f-f695-474a-9f08-47b85fcac366': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/f2e0c9f3-ab0d-441a-85a6-07a42e78b5a8/848f353e-6787-4e20-ab7b-0541ebd852c6', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '26332421-54a3-4afc-90e7-551a7e314c80': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/b7a785f9-307b-42af-9bbe-23cac884fe97/ed1d027e-a36a-4e6b-9207-119915044e06', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '60edbd80-dad7-4bf8-8fd1-e138413cf9f6': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/535fcb2e-ece9-4d50-86fe-bf6264d11ae1/6c01a036-8a14-46ba-a4b4-fe4f66a586a3', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdb', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/1f467fb5-5ea7-42ba-bace-f175c86791b2/cbe8327f-9b7f-442f-a650-6888bb11a674', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdd', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/c93956d5-c88d-41f9-8c38-9f5f62cc90dd/3920b46c-5fab-4b63-b47f-2fa5c6714c36', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, 'beeefe06-78a0-4e14-a932-cc8d734d542d': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/glusterSD/gluster0.grove.silverorange.com:_data__sdb/30fd0a2f-ab42-4a8a-8f0b-67242dc2d15d/images/310d8b3e-d578-418d-9802-dc0ebcea06d6/aa758c51-8478-4273-aeef-d4b374b8d6b4', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdb', 'path': '/rhev/data-center/mnt/glusterSD/gluster0.grove.silverorange.com:_data__sdb/30fd0a2f-ab42-4a8a-8f0b-67242dc2d15d/images/4072fda1-ec82-45c9-b353-91fceb13bf08/891f5982-dead-48b4-8907-caa1e309fa82', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '7e5156de-649d-4904-9092-21a699242a37': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/ca0c1208-a7aa-4ef6-a450-4a40bd4455f3/a2335199-ddd4-429b-b55d-f4d527081fd3', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}}} from=::1,35012 (api:54)
2021-05-27 17:10:41,120+0000 WARN  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration stalling: remaining (32863MiB) > lowmark (32863MiB). (migration:801)
2021-05-27 17:10:41,120+0000 INFO  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration Progress: 200.037 seconds elapsed, 1% of data processed, total data: 32864MB, processed data: 0MB, remaining data: 32863MB, transfer speed 0Mbps, zero pages: 160MB, compressed: 0MB, dirty rate: 0, memory iteration: 1 (migration:814)
2021-05-27 17:10:51,121+0000 WARN  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration stalling: remaining (32863MiB) > lowmark (32863MiB). (migration:801)
2021-05-27 17:10:51,121+0000 INFO  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration Progress: 210.039 seconds elapsed, 1% of data processed, total data: 32864MB, processed data: 0MB, remaining data: 32863MB, transfer speed 0Mbps, zero pages: 160MB, compressed: 0MB, dirty rate: 0, memory iteration: 1 (migration:814)
2021-05-27 17:10:52,211+0000 INFO  (jsonrpc/1) [api.host] FINISH getAllVmIoTunePolicies return={'status': {'code': 0, 'message': 'Done'}, 'io_tune_policies_dict': {'f8f4e4a1-b565-4663-8962-c8804dbb86fb': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme1n1/bce04425-1d25-4489-bdab-2834a1a57db8/images/38b27cce-c744-4a12-85a3-3af07d386da2/93c1e793-f8cb-42c9-86a6-0e9ce4a6023a', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '2b87204f-f695-474a-9f08-47b85fcac366': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/f2e0c9f3-ab0d-441a-85a6-07a42e78b5a8/848f353e-6787-4e20-ab7b-0541ebd852c6', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '26332421-54a3-4afc-90e7-551a7e314c80': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/b7a785f9-307b-42af-9bbe-23cac884fe97/ed1d027e-a36a-4e6b-9207-119915044e06', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '60edbd80-dad7-4bf8-8fd1-e138413cf9f6': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/535fcb2e-ece9-4d50-86fe-bf6264d11ae1/6c01a036-8a14-46ba-a4b4-fe4f66a586a3', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdb', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/1f467fb5-5ea7-42ba-bace-f175c86791b2/cbe8327f-9b7f-442f-a650-6888bb11a674', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdd', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme2n1/a7efa448-201b-4453-9bc9-900559b891ca/images/c93956d5-c88d-41f9-8c38-9f5f62cc90dd/3920b46c-5fab-4b63-b47f-2fa5c6714c36', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, 'beeefe06-78a0-4e14-a932-cc8d734d542d': {'policy': [], 'current_values': [{'name': 'sda', 'path': '/rhev/data-center/mnt/glusterSD/gluster0.grove.silverorange.com:_data__sdb/30fd0a2f-ab42-4a8a-8f0b-67242dc2d15d/images/310d8b3e-d578-418d-9802-dc0ebcea06d6/aa758c51-8478-4273-aeef-d4b374b8d6b4', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}, {'name': 'sdb', 'path': '/rhev/data-center/mnt/glusterSD/gluster0.grove.silverorange.com:_data__sdb/30fd0a2f-ab42-4a8a-8f0b-67242dc2d15d/images/4072fda1-ec82-45c9-b353-91fceb13bf08/891f5982-dead-48b4-8907-caa1e309fa82', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}, '7e5156de-649d-4904-9092-21a699242a37': {'policy': [], 'current_values': [{'name': 'vda', 'path': '/rhev/data-center/mnt/10.11.0.9:_vmstorage_nvme0n1/a99cd663-f6d5-42d8-bd7a-ee0b5d068608/images/ca0c1208-a7aa-4ef6-a450-4a40bd4455f3/a2335199-ddd4-429b-b55d-f4d527081fd3', 'ioTune': {'total_bytes_sec': 0, 'read_bytes_sec': 0, 'write_bytes_sec': 0, 'total_iops_sec': 0, 'write_iops_sec': 0, 'read_iops_sec': 0}}]}}} from=::1,35012 (api:54)
2021-05-27 17:11:01,123+0000 WARN  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration stalling: remaining (32863MiB) > lowmark (32863MiB). (migration:801)
2021-05-27 17:11:01,123+0000 INFO  (migmon/7e5156de) [virt.vm] (vmId='7e5156de-649d-4904-9092-21a699242a37') Migration Progress: 220.041 seconds elapsed, 1% of data processed, total data: 32864MB, processed data: 0MB, remaining data: 32863MB, transfer speed 0Mbps, zero pages: 160MB, compressed: 0MB, dirty rate: 0, memory iteration: 1 (migration:814)ats return={'86245648-abd8-46e3-9c10-432e8788a074': {'code': 0, 'lastCheck': '1.6', 'delay': '0.00353497', 'valid': True, 'version': 5, 'acquired': True, 'actual': True}} from=::1,35010, task_id=c4e65f55-1367-41d3-9bf6-f357a382df4a (api:54)
2021-05-27 17:09:33,156+0000 INFO  (jsonrpc/2) [api.host] START getStats() from=::ffff:10.11.0.219,54952 (api:48)