Hello,<br><br>I've been using drbd for about 5 years now, and it has been working great.<br><br>Recently we modified the setup, moved a couple of servers around, so drbd should replicate over a 20 Mbit/sec WAN line.<br>
<br>I've changed from Protocol C to A, and enabled Ahead/Behind mode. It seems to work, but after some time, some of the resources stuck in Ahead/Behind mode and never resync again unless I disconnect and reconnect the resource.<br>
<br>It looks like this on the Primary:<br>cat /proc/drbd <br>version: 8.4.1 (api:1/proto:86-100)<br>GIT-hash: bb796da897912034a90003910f69ae0a2c10cf44 build by root@node1, 2012-06-04 13:02:39<br>[..]<br>13: cs:Ahead ro:Primary/Secondary ds:UpToDate/Inconsistent A r-----<br>
ns:9428820 nr:0 dw:446339296 dr:931364896 al:280851 bm:66801 lo:0 pe:0 ua:0 ap:0 ep:1 wo:n oos:1389708<br><br>A minute later:<br><br>13: cs:Ahead ro:Primary/Secondary ds:UpToDate/Inconsistent A r-----<br> ns:9428820 nr:0 dw:446340428 dr:931364948 al:280851 bm:66801 lo:0 pe:0 ua:0 ap:0 ep:1 wo:n oos:1389728<br>
<br>This seems like a bug to me, and it has already been reported by someone else in August: <a href="http://lists.linbit.com/pipermail/drbd-user/2012-August/018934.html">http://lists.linbit.com/pipermail/drbd-user/2012-August/018934.html</a><br>
<br>I've also created a virtualised testsetup with two nodes with 8.4.2, and I could reach this state, so it is fairly reproducible. The problem seems to be happening when the node switches from SyncSource to Ahead mode without finishing synchronization, i.e. I finish some writing to the drbd device, then wait a few seconds so the node starts to sync, then I start writing again. <br>
<br>On the productive system it happens on resources which has the most writes. <br><br>Any help is appreciated.<br><br>Bye.<br><br>The configuration:<br><br> cat /usr/local/etc/drbd.d/global_common.conf<br>global {<br> usage-count no;<br>
}<br><br>common {<br> net {<br> protocol A;<br> max-buffers 2048;<br> max-epoch-size 2048;<br> verify-alg sha1;<br> csums-alg sha1;<br> }<br> disk {<br> disk-barrier no;<br>
disk-flushes no;<br> md-flushes no;<br> disk-drain no;<br> al-extents 1801;<br> }<br> startup {<br> wfc-timeout 180;<br> degr-wfc-timeout 120;<br>
}<br>}<br><br>cat /usr/local/etc/drbd.d/r13.res <br><br>resource r13 {<br><br> net {<br> protocol A;<br> on-congestion pull-ahead;<br> congestion-fill 200k;<br> congestion-extents 1620;<br>
}<br><br> disk {<br> c-max-rate 1500k;<br> }<br><br> on node1 {<br> device /dev/drbd13 minor 13;<br> disk /dev/sda5;<br> meta-disk internal;<br> address ipv4 <a href="http://10.129.164.130:7801">10.129.164.130:7801</a>;<br>
}<br> on node2 {<br> device /dev/drbd13 minor 13;<br> disk /dev/sdb7;<br> meta-disk internal;<br> address ipv4 <a href="http://10.129.166.125:7801">10.129.166.125:7801</a>;<br>
}<br>}<br><br><br>