<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><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? </div><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 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>
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