Hi Karl,

Since some of the details are missing, I'm going to assume that:

1. You are running 'master' version of OpenStack or at least one of the extended maintenance release

2. The operation is a retype with migration using the generic migration path

3. The volumes are in 'available' state and NOT attached to any VM workload

With the above assumptions, you can use ``use_multipath_for_image_xfer`` option to enable multipathing while migrating volumes.

Thanks
Rajat Dhasmana

On Mon, Jan 12, 2026 at 7:44 PM Karl-Heinz Preuß <preuss@b1-systems.de> wrote:

Hi Everyone,

I'm trying to migrate cinder volumes from one backend to another. Namely
I'm migrating from an HPE Nimble Storage backend to a Ceph backend.

My Problem: the volume migration speed is kinda sluggish - around 100
MB/s. I can read from a Nimble backed volume way faster. And of course
the Ceph can also write more than 1GB/s.

After quite some debugging, the problem seems to be: cinder uses
multipathing to access the Nimble backed volumes. But for some reason
cinder's volume migration explicitly doesn't use multipathing.
(I found "multipath=false" in the cinder logs when looking for my slow
migrations.)

Question: is there a way to configure cinder to use multipathing for
volume migrations when available.

--
Karl-Heinz Preuß
Linux Consultant
Tel.: +49 1515 5806243
E-Mail: preuss@b1-systems.de

B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / https://www.b1-systems.de
GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt, HRB 3537