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<p>The Stein release notes mention that the RBD driver now supports
multiattach, but i have not found any details. Are there
limitations? Is there a need to configure anything?</p>
<p><a moz-do-not-send="true"
href="https://opendev.org/openstack/cinder/src/branch/master/cinder/volume/drivers/rbd.py#L767">In
the RBD driver</a>, I find this:</p>
<pre> def _enable_multiattach(self, volume):
multipath_feature_exclusions = [
self.rbd.RBD_FEATURE_JOURNALING,
self.rbd.RBD_FEATURE_FAST_DIFF,
self.rbd.RBD_FEATURE_OBJECT_MAP,
self.rbd.RBD_FEATURE_EXCLUSIVE_LOCK,
]</pre>
<p>This seems to mean that journaling and other features (to me,
it's not quite clear what they are) will be automatically disabled
when switching on multiattachment.</p>
<p>Further down in the code I see that replication and multiattach
are mutually exclusive.</p>
<p>Is there some documentation about the Ceph multiattach feature,
even an email thread?</p>
<p>Thanks,</p>
<p>Bernd<br>
<code class="py hljs python"></code></p>
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