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<div class="moz-cite-prefix">On 16/08/2016 07:09, Craig Thompson
wrote:<br>
</div>
<blockquote
cite="mid:zarafa.57b22f9c.110a3.36bef10930b56ca@z.xc.org"
type="cite">
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<title>Basic DRBD link not syncing</title>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">First post to
the list. I've tried using search engines to find this info
but haven't so far.</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">I have two
servers. They each run Xen hypervisor to support guest
virtual machines. They each have multiple LVMs for the
underlying disk images of the virtual machines.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"></span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">I have set up
Machine A to be the Primary for Guest1. Machine B is the
Secondary for Guest1.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">The config I
have for each looks like this:<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">resource
guest1 {<br>
net { protocol C; }<br>
device /dev/drbd3;<br>
disk /dev/vg0/guest3;<br>
meta-disk internal;<br>
syncer { verify-alg "md5" ; }<br>
<br>
on primary.host.domain {<br>
address 192.168.1.10:7789;<br>
}<br>
<br>
on secondary.host.domain {<br>
address 192.168.1.20:7789;<br>
}<br>
}<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">I can use
drbdadm and bring the resources up. I can force a primary.
This initiates a full sync the first time.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">However, if I
emulate an outage on Machine B (secondary) for minutes or
hours and then bring it back online, the syncing doesn't
continue automatically.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">I don't know
what I'm missing in configuration(s). I may be missing
something in the overall picture. But what I WANT to have
happen is that DRBD sees when the link is down, pauses and
then picks up syncing after an outage on the remote end.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">If I run a
'drbdadm verify guest1', then it will initiate a review, sync
the out of sync blocks and then say it's up to date. <br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
But if I go to the Machine A and create a new file on guest1,
then shut down guest1 so that no other changes are made, and
then I go to Machine B and bring guest1 up, the newly created
file is NOT there.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">So, I'm
missing some key component that KEEPS things syncing after the
initial sync is completed.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">Help?
Documentation pointers? FAQs? How-Tos?<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;">Thanks in
advance.<br>
</span></p>
<p style="padding: 0; margin: 0;"><span style="font-size: 10pt;
font-family: tahoma,arial,helvetica,sans-serif;"><br>
</span></p>
</blockquote>
There was a similar question on the list just a few days ago, not
sure if that was you. <br>
In any case, the best thing to check/verify is that your VM is
accessing /dev/drbd3 and that nothing (except DRBD itself) is
accessing /dev/vg0/guest3 (on both primary and secondary).<br>
<br>
Any changes made to /dev/vg0/guest3 are unknown to DRBD, and so DRBD
will not know that they should be synced to the other node. It is
the same as creating a MD array with /dev/sda1 and /dev/sdb1 as
/dev/md1 and then writing to /dev/sda1 and complaining there is not
consistent data on /dev/sdb1.<br>
<br>
I hope that helps, if not, please see if you can include a step by
step process, with all commands you entered, all output generated
from each step, which will show the problem.<br>
<br>
Regards,<br>
Adam<br>
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