Delay deleting source share server after migration

[chuan137]

Hi,

It's a feedback from operations and I feel it might be interesting for wider audiences.

We are offloading payloads from old filers with the share server migration feature. In current Manila implementation, the source share servers are deleted from both Manila and storage backend immediately after migration complete (cut-over).

However, we might need to roll back the migration for some reasons. Although small chances, it would be nice to have the option to delay the cleanups for a period of time, and only prune them automatically afterwards. This will make it easier to execute rolling back procedures on backend.

Best,
Chuan

[Vida Haririan (vhariria)]

See additional related discussions at https://meetings.opendev.org/meetings/manila/2023/manila.2023-07-27-15.00.log.html

[Carlos Eduardo (silvacarlose)]

Hi Chuan!

Thanks for raising this bug report. We discussed this at a weekly IRC meeting and have a couple of questions:

1) Can you please share the migration command you used? we're interested to know if you're performing a nondisruptive share migration; where we believe manila is cleaning up the share servers immediately: https://github.com/openstack/manila/blob/3b9cfe126fbb5d83febe6f9f8747be3c4ce787c4/manila/share/manager.py#L5823-L5839
Otherwise, it could take some time for the share server deletion routine to pick up the share server and delete it.

2) How do you plan to rollback? If a nondisruptive migration occurred, we expect that the storage system doesn't have the share server in the original host; and a rollback would really be a different migration operation.

[chuan137 (chuan137)]

Hi Carlos,

Thanks for the discussions. For your questions,

1) yes, it's nondisruptive share server migration. The command, for example, is

> manila --debug share-server-migration-check f27a1096-38af-4a6e-801f-86fa7235e347 manila-share-netapp-ma01-st051@ma01-st051 --preserve-snapshots True --writable True --nondisruptive True

2) I don't know the details about the rollback procedures. Our storage team colleagues told me that NetApp has shared a procedure. I will ask them what the need for keeping the share servers.

Best,
Chuan