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<div class="moz-cite-prefix">If I did not misunderstand what this is
about, then the problem seem to be this:<br>
<br>
You are using a DRBD device as the physical volume for a volume
group. As soon as something changes in that volume group, e.g. you
add or remove volumes (such as snapshots), the metadata for that
volume group on the physical volume changes.<br>
That is what you replicate to the peer (the secondary), so all the
LVM on the peer can see, is data magically changing on its
physical volume, and that's where the kernel Oops is coming from,
because data is not supposed to change without the local node
knowing about it. This is an unsafe scenario unless there is some
kind of synchronization in place on the LVM level (e.g. "Clustered
LVM" aka CLVM -- instead of the normal LVM, which is not designed
to operate on shared or replicated storage).<br>
<br>
br,<br>
Robert<br>
<br>
On 06/22/2015 11:06 AM, Paul Gideon Dann wrote:<br>
</div>
<blockquote
cite="mid:CALZj-Vru7yS=eZzzxPtTV8DgO9gs=G7C48B1-M50Tm2sGGoy0A@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>
<div>So no ideas concerning this, then? I've seen the same
thing happen on another resource, now. Actually, it doesn't
need to be a snapshot: removing any logical volume causes
the oops. It doesn't happen for every resource, though.<br>
<br>
[...snip...]<br>
</div>
<br>
</div>
Paul<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On 16 June 2015 at 11:51, Paul Gideon
Dann <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:pdgiddie@gmail.com" target="_blank">pdgiddie@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>This is an interesting (though frustrating) issue
that I've run into with DRBD+LVM, and having finally
exhausted everything I can think of or find myself, I'm
hoping the mailing list might be able to offer some
help!<br>
<br>
</div>
<div>My setup involves DRBD resources that are backed by
LVM LVs, and then formatted as PVs themselves, each
forming its own VG.<br>
<br>
</div>
<div>System VG -> Backing LV -> DRBD -> Resource
VG -> Resource LVs<br>
<br>
</div>
<div>The problem I'm having happens only for one DRBD
resource, and not for any of the others. This is what I
do:<br>
<br>
</div>
<div>I create a snapshot of the Resource LV (meaning that
the snapshot will also be replicated via DRBD), and
everything is fine. However, when I *remove* the
snapshot, the *secondary* peer oopses immediately:<br>
<br>
[...snip...]<br>
<br>
</div>
<div>Cheers,<br>
</div>
<div>Paul<br>
</div>
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