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I have a setup where I can reliably reproduce the following within a
few minutes:<br>
<br>
<font style="margin: 0px; padding: 0px; border: 0px; vertical-align:
baseline;" face="courier new, monospace" size="1">Jul 11 10:59:46
wrn-vm2 kernel: [236603.130604] block drbd0: uuid_compare()=-1 by
rule 35</font>
<div style="margin: 0px; padding: 0px; border: 0px; vertical-align:
baseline; color: rgb(34, 34, 34); font-family: Arial, Helvetica,
sans-serif; font-size: 13px; font-style: normal; font-variant:
normal; font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);"><font style="margin: 0px;
padding: 0px; border: 0px; vertical-align: baseline;"
face="courier new, monospace" size="1">Jul 11 10:59:46 wrn-vm2
kernel: [236603.135779] block drbd0: I shall become SyncTarget,
but I am primary!</font></div>
<div style="margin: 0px; padding: 0px; border: 0px; vertical-align:
baseline; color: rgb(34, 34, 34); font-family: Arial, Helvetica,
sans-serif; font-size: 13px; font-style: normal; font-variant:
normal; font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: auto;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(255, 255, 255);"><font style="margin: 0px;
padding: 0px; border: 0px; vertical-align: baseline;"
face="courier new, monospace" size="1">Jul 11 10:59:46 wrn-vm2
kernel: [236603.142336] block drbd0: ASSERT( os.conn ==
C_WF_REPORT_PARAMS ) in /build/linux-s5x2oE/linux-3.2.<wbr>46/drivers/block/drbd/drbd_<wbr>receiver.c:3245</font></div>
<br>
It's on Debian Wheezy with Debian stock kernel (3.2.0-4-amd64).<br>
<br>
Jun 25 15:01:27 wrn-vm1 kernel: [ 626.901545] drbd: initialized.
Version: 8.3.11 (api:88/proto:86-96)<br>
Jun 25 15:01:27 wrn-vm1 kernel: [ 626.901547] drbd: srcversion:
F937DCB2E5D83C6CCE4A6C9<br>
<br>
There are more details in this thread:<br>
<a class="moz-txt-link-freetext"
href="https://groups.google.com/forum/#%21topic/ganeti/icqLNFk1si0">https://groups.google.com/forum/#!topic/ganeti/icqLNFk1si0</a><br>
<br>
I am reproducing it using ganeti, which uses drbd on top of LVM
logical volumes to replicate virtual machine images. It migrates
virtual machines by sending drdbsetup commands to switch
master->slave replication firstly to multi-master, and then to
slave<-master (apparently by disconnecting and reconnecting). I
believe there is some sort of race condition going on, because (a)
it seems few if any other people observe what I see; and (b)
although I can reproduce the problem within a few minutes, if I
attach a full-blown strace to the process which is issuing the
drbdsetup calls, the problem goes away.<br>
<br>
The google groups thread includes an strace log of execve() calls,
so you can see what sequence of drbdsetup calls are being issued. Is
it possible that ganeti is taking an unsafe approach to switching
over the drbd state?<br>
<br>
Regards,<br>
<br>
Brian Candler.<br>
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