<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<br>
<div class="moz-cite-prefix">On 11/23/2014 04:59 AM, Nipun Arora
wrote:<br>
</div>
<blockquote
cite="mid:CAA9cJVV9E2g=vfcbh8QwRF2HGahrMHunf2os3whbufzqF7UH-Q@mail.gmail.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<div dir="ltr">Hi Kir,
<div><br>
</div>
<div>Thanks for the response, I'll update it, and tell you about
the results.</div>
<div><br>
</div>
<div>1. A follow up question... I found that the write I/O speed
of 500-1Mbps increased the suspend time to several
minutes.(mostly pcopy stage)</div>
<div>This seems extremely high for a relatively low I/O
workload, which is why I was wondering if there are any
special things I need to take care of.</div>
<div>(I ran fio (flexible i/o writer) with fixed throughput
while doing live migration)</div>
</div>
</blockquote>
<br>
Please retry with vzctl 4.8 and ploop 1.12.1 (make sure they are on
both sides).<br>
There was a 5 second wait for the remote side to finish syncing<br>
copied ploop data. It helped a case with not much I/O activity in
container, but<br>
ruined the case you are talking about.<br>
<br>
Newer ploop and vzctl implement a feedback channel for ploop copy
that eliminates<br>
that wait time. <br>
<br>
<a class="moz-txt-link-freetext" href="http://git.openvz.org/?p=ploop;a=commit;h=20d754c91079165b">http://git.openvz.org/?p=ploop;a=commit;h=20d754c91079165b</a><br>
<a class="moz-txt-link-freetext" href="http://git.openvz.org/?p=vzctl;a=commit;h=374b759dec45255d4">http://git.openvz.org/?p=vzctl;a=commit;h=374b759dec45255d4</a><br>
<br>
There are some other major improvements as well, such as async send
for ploop.<br>
<br>
<a class="moz-txt-link-freetext" href="http://git.openvz.org/?p=ploop;a=commit;h=a55e26e9606e0b">http://git.openvz.org/?p=ploop;a=commit;h=a55e26e9606e0b</a><br>
<blockquote
cite="mid:CAA9cJVV9E2g=vfcbh8QwRF2HGahrMHunf2os3whbufzqF7UH-Q@mail.gmail.com"
type="cite">
<div dir="ltr">
<div><br>
</div>
<div>2. <span
style="font-family:arial,sans-serif;font-size:13px">For my
purposes, I have modified the live migration script to allow
me to do cloning... i.e. I start both the containers instead
of deleting the original. I need to do this "cloning" from
time to time for the same target container... </span></div>
<div style="font-family:arial,sans-serif;font-size:13px"><br>
</div>
<div style="font-family:arial,sans-serif;font-size:13px">
a. Which means that lets say we cloned container C1 to
container C2, and let both execute at time t0, this works with
no apparent loss of service.</div>
<div style="font-family:arial,sans-serif;font-size:13px"> </div>
<div style="font-family:arial,sans-serif;font-size:13px">
b. Now at time t1 I would like to again clone C1 to C2, and
would like to optimize the rsync process as most of the ploop
file for C1 and C2 should still be the same (i.e. less time to
sync). Can anyone suggest what would be the best way to
realize the second point? <br>
</div>
</div>
</blockquote>
<br>
You can create a ploop snapshot and use shared base image for both
containers<br>
(instead of copying the base delta, hardlink it). This is not
supported by tools<br>
(for example, since base delta is now shared you can't merge down to
it, but the<br>
tools are not aware) so you need to figure it out by yourself and be
accurate<br>
but it should work.<br>
<br>
<blockquote
cite="mid:CAA9cJVV9E2g=vfcbh8QwRF2HGahrMHunf2os3whbufzqF7UH-Q@mail.gmail.com"
type="cite">
<div dir="ltr">
<div><br>
</div>
<div><br>
</div>
<div>Thanks</div>
<div>Nipun</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sun, Nov 23, 2014 at 12:56 AM, Kir
Kolyshkin <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:kir@openvz.org" target="_blank">kir@openvz.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"><span class=""> <br>
<div>On 11/22/2014 09:09 AM, Nipun Arora wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi All,
<div><br>
</div>
<div>I was wondering if anyone can suggest what is
the most optimal way to do the following</div>
<div><br>
</div>
<div>1. Can anyone clarify if ploop is the best
layout for minimum suspend time during live
migration?</div>
</div>
</blockquote>
<br>
</span> Yes (due to ploop copy which only copies the
modified blocks).<span class=""><br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>2. I tried migrating a ploop device where I
increased the --diskspace to 5G,<br>
and found that the suspend time taken by live
migration increased to 57 seconds<br>
(mainly undump and restore increased)...<br>
whereas a 2G diskspace was taking 2-3 seconds
suspend time... Is this expected?</div>
<div><br>
</div>
</div>
</blockquote>
<br>
</span> No. Undump and restore times depends mostly on
amount of RAM used by a container.<br>
<br>
Having said that, live migration stages influence each
other, although it's less so<br>
in the latest vzctl release (I won't go into details here
if you allow me -- just make sure<br>
you test with vzctl 4.8).<span class=""><br>
<br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div>3. I tried running a write intensive workload,
and found that beyond 100-150Kbps,<br>
the suspend time during live migration rapidly
increased? Is this an expected trend?</div>
</div>
</blockquote>
<br>
</span> Sure. With increased writing speed, the amount of
data that needs to be copied after CT<br>
is suspended increases.<span class=""><br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>I am using vzctl 4.7, and ploop 1.11 in centos
6.5</div>
</div>
</blockquote>
<br>
</span> You need to update vzctl and ploop and rerun your
tests, there should be<br>
some improvement (in particular with respect to issue #3).<span
class=""><br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>Thanks</div>
<div>Nipun</div>
</div>
<br>
<fieldset></fieldset>
<br>
<pre>_______________________________________________
Users mailing list
<a moz-do-not-send="true" href="mailto:Users@openvz.org" target="_blank">Users@openvz.org</a>
<a moz-do-not-send="true" href="https://lists.openvz.org/mailman/listinfo/users" target="_blank">https://lists.openvz.org/mailman/listinfo/users</a>
</pre>
</blockquote>
<br>
</span></div>
<br>
_______________________________________________<br>
Users mailing list<br>
<a moz-do-not-send="true" href="mailto:Users@openvz.org">Users@openvz.org</a><br>
<a moz-do-not-send="true"
href="https://lists.openvz.org/mailman/listinfo/users"
target="_blank">https://lists.openvz.org/mailman/listinfo/users</a><br>
<br>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Users@openvz.org">Users@openvz.org</a>
<a class="moz-txt-link-freetext" href="https://lists.openvz.org/mailman/listinfo/users">https://lists.openvz.org/mailman/listinfo/users</a>
</pre>
</blockquote>
<br>
</body>
</html>