Unable to live migrate VM between 2 local storages SR

henri9813

Hello.

I have this error while trying to migrate VM from a host to another host. ( same versions ).

Jul 10 10:58:06 server xapi: [debug||3148384 ||storage_utils] Got failure: checking for redirect, call was: -> SR.scan({sr:S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff);dbg:S(Async.VM.migrate_send R:afa4f5b49fd9)}), results.contents: ["No_storage_plugin_for_sr","a2e6300f-10f2-ec61-bcfb-6a1d62a00bff"]
Jul 10 10:58:06 server xapi: [debug||3148384 ||storage_utils] Not a redirect: -> SR.scan({sr:S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff);dbg:S(Async.VM.migrate_send R:afa4f5b49fd9)})
Jul 10 10:58:06 server xapi: [error||3148384 ||storage_interface] Storage_error ([S(No_storage_plugin_for_sr);S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff)]) (File "ocaml/xapi-idl/storage/storage_interface.ml", line 451, characters 49-56)
Jul 10 10:58:06 server xapi: [error||3148384 ||storage_migrate] Storage_migrate.MigrateLocal.prepare Caught error Storage_error ([S(No_storage_plugin_for_sr);S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff)]) while preparing for SXM
Jul 10 10:58:06 server xapi: [error||3148384 ||storage_migrate] Caught Storage_error ([S(Migration_preparation_failure);S(Storage_error ([S(No_storage_plugin_for_sr);S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff)]))]) during SXM:
Jul 10 10:58:06 server xapi: [error||3148384 ||task_server] Task 3 failed; Storage_error ([S(Internal_error);S(Storage_error ([S(Migration_preparation_failure);S(Storage_error ([S(No_storage_plugin_for_sr);S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff)]))]))])
Jul 10 10:58:06 server xapi: [debug||3148384 ||storage] TASK.signal 3 = ["Failed",["Internal_error","Storage_error ([S(Migration_preparation_failure);S(Storage_error ([S(No_storage_plugin_for_sr);S(a2e6300f-10f2-ec61-bcfb-6a1d62a00bff)]))])"]]

Do you know what No_storage_plugin_for_sr mean ?

It's a simple local storage

henri9813

Hello.

Problem Solved.

My case:

i have a pool of many hypervisors with only local storage, no shared SR ( yes it's not recommanded, i stopped doing this and i'm currently migrating everything to pool with Shared storage ).

Yesterday, i removed two hosts ( host 3 & host 4 ) whith local storages SR attached ( LVM ).

In XCP-NG, i "forgot" Host 3 & host 4, the hosts from the pool, but it doesn't forge the associated SR !

But Live migrating a VM from host 1 to host 2 ( of the same pool ) bot with local SR, FAIL because there is no SR plugin attached of Local Storage 4 ( hosts 4 ) neither Local storage 3 ( host 3 ).

So, i also forget theses 2 SRs and now it's ok.

i don't understand why SR not connected to anyone can prevent migration about vm from other to other sr.

poddingue

Thanks for coming back and writing up what fixed it.

I don't know why a disconnected SR blocks a migration between two other SRs. My guess, and it's only a guess, is that VM.migrate_send runs an SR.scan across every SR in the pool rather than just the source and the target, so one leftover SR with no plugin attached is enough to kill the whole prepare step.
There is a troubleshooting entry with your symptom at https://docs.xcp-ng.org/troubleshooting/common-problems#unable-to-live-migrate-vdi-between-srs, but it only lists the empty xapi-pool-ca-bundle.pem cause, not orphaned SRs left behind after a host-forget. So it wouldn't have helped you anyway.

Might be worth a mention to @Team-Storage, both to confirm the mechanism and maybe to get your case added to that page.

henri9813

Hello @poddingue , you right.

Yes i saw this article, but it was unrelated to my issue.

I agree your guess.

How can i mark the topic as Solved ?

poddingue

I converted the topic to a question, then marked it solved.
Thanks!