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

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