<div dir="ltr"><div>On Sun, Jun 16, 2013 at 6:44 AM, cesar <span dir="ltr"><<a href="mailto:brain@click.com.py" target="_blank">brain@click.com.py</a>></span> wrote:<br></div><div class="gmail_extra"><div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Right digimar, Red Hat did the fence software.<br>
<br>
Only for comment, please see this link of Red Hat, and you will see that<br>
"fence_ack_manual" is supported:<br>
<a href="https://access.redhat.com/site/articles/27136" target="_blank">https://access.redhat.com/site/articles/27136</a><br></blockquote><div> </div><div>In my opinion "fence_ack_manual" is supported to escape from situations where the fencing mechanism is not working as expected e.g. (from the article you just cited) "<strong style="font-size:13px;border:0px;margin:0px;padding:0px;vertical-align:baseline;color:rgb(51,51,51);font-family:'Liberation Sans',Arimo,'Trebuchet MS','Bitstream Vera Sans',helvetica,verdana,arial,sans-serif;line-height:18px">site-to-site link failure would prevent fencing from working between the sites"</strong></div>
<div>So as Digimar already told: *you need fencing*!! I think it is the last time some one tell you: *you need fencing*!!</div><div> <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
And about DRBD over a direct connection in mode round robin, can you give me<br>
links or comments about this case? (This is very important for me because I<br>
will lose connection speed if I change of balance-rr to active-backup).<br></blockquote><div><br></div><div><a href="https://www.kernel.org/doc/Documentation/networking/bonding.txt" target="_blank">https://www.kernel.org/doc/Documentation/networking/bonding.txt</a><br>
</div><div><pre style="white-space:pre-wrap;word-wrap:break-word">balance-rr: This mode is the only mode that will permit a single
TCP/IP connection to stripe traffic across multiple
interfaces. It is therefore the only mode that will allow a
single TCP/IP stream to utilize more than one interface's
worth of throughput. This comes at a cost, however: the
striping generally results in peer systems receiving packets out
of order, causing TCP/IP's congestion control system to kick
in, often by retransmitting segments.</pre></div><div>The problem is you have out of order packets and it doesn't help if you start to play around with <span style="white-space:pre-wrap">net.ipv4.tcp_reordering sysctl parameter</span> </div>
<div>because there will always be a chance to have out of order packets. Ordered packets are indeed fundamental to DRBD.</div><div>In DRBD world the bonding driver is used to achieve HA using active/backup or 802.3ad. Neither of which will boost your performance (802.3ad can improve performance if and only if you have a great number of TCP connections but that's not the case with your DRBD scenario).</div>
<div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
In either case, I am grateful to you for your kind attention, your time and<br>
your information.<br>
<br>
Best regards<br>
Cesar</blockquote><div><br></div><div>I *think* balance-rr bonding mode (and out of order packets) could be the source of your specific problem:</div><div><span style="font-family:arial,sans-serif;font-size:13px">Jun 14 08:50:12 kvm5 kernel: block drbd0: Digest mismatch, buffer modified </span><span style="font-family:arial,sans-serif;font-size:13px">by upper layers during write: 21158352s +4096</span><br>
</div><div><span style="font-family:arial,sans-serif;font-size:13px">Jun 14 08:50:12 kvm6 kernel: block drbd0: Digest integrity check FAILED: </span><span style="font-family:arial,sans-serif;font-size:13px">21158352s +4096</span><br>
</div><div style>So just try to go active/backup bonding mode and let's see what happens but please do remember: You need fancing!</div><div>
</div><div>Cheers,</div><div style>Luca</div></div></div></div>