<div dir="ltr">On Wed, Jan 2, 2013 at 3:53 AM, Robert Dinse <span dir="ltr"><<a href="mailto:nanook@eskimo.com" target="_blank">nanook@eskimo.com</a>></span> wrote:<br><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"><br>
Friday, I moved our servers to a new co-lo facility and ran into an<br>
interesting problem with virtual machines.<br>
<br>
I did an orderly shutdown of the CentOS 6.3 host, and it in turn suspends<br>
all the guests. It took about an hour and a half to move and fire up the host.<br>
<br></blockquote><div><br></div><div style>By default VMs suspend when the host node is shutdown. You can change this behavior in /etc/sysconfig/libvirt-guests</div><div style><br></div><div style>By shutting down the VMs you don't have to wait for the in-memory data to be dumped to disk, nor do you have to wait for it to be copied back from disk and into memory on boot.</div>
<div> </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">
The guests, being suspended, were then an hour and a half behind and it<br>
seems ntpd does not want to correct more than 1000 seconds of error so it would<br>
not automatically adjust the clocks.<br></blockquote><div><br></div><div style>At my place of employment we noticed the same thing during maintenance, the VMs had their clocks all out of whack.</div><div> </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">
<br>
I tried the -g argument which is supposed to override the 1000 second<br>
limit but it did not. I ended up having to manually set the clocks close<br>
enough for ntpd to correct.<br>
<br></blockquote><div><br></div><div style>I believe we had manually correct the clocks as well on ours, but it's been months since then.</div><div> </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">
Since there is no hardware clock for the virtual machines to use when they<br>
boot, it seems that shutdown and reboot of the virtual machines probably would<br>
not have avoided this.<br>
<br>
Any suggestions for addressing this particular scenerio other than having<br>
to manually set a bunch of clocks?<br>
<br>
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</blockquote></div><br>-- <br>---~~.~~---<br>Mike<br>// SilverTip257 //
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