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On 10/09/2011 02:21 PM, Yibin Shen wrote:
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cite="mid:CAJL_2EFdCRgy65fs=ZY3BnPWLpZaF1+iOFoxQC59fOUc1eSDig@mail.gmail.com"
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<div class="gmail_quote">On Sun, Oct 9, 2011 at 1:33 PM, Liu Yuan
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<<a moz-do-not-send="true"
href="mailto:namei.unix@gmail.com">namei.unix@gmail.com</a>></span>
wrote:<br>
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<div class="im">On 10/09/2011 01:07 PM, MORITA Kazutaka wrote:<br>
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At Sun, 9 Oct 2011 11:21:52 +0800,<br>
Yibin Shen wrote:<br>
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Use mmap is much simpler than local backup image, and
without<br>
any influence to consistency. but it doesn't improve
availability<br>
while whole sheepdog cluster is die(such as some odd
network<br>
partition issue).<br>
<br>
anyway, if no one againsts, I will try to implement it
in the<br>
near future (after we solved most stability issues)<br>
</blockquote>
Can we implement it as an extension of the cache
mechanism? If the<br>
local cache file has whole data in the Sheepdog VDI, we
can regard it<br>
as a local backup image.<br>
<br>
Thanks,<br>
<br>
Kazutaka<br>
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Maybe we can read-ahead in the whole data if network is not
busy gradually? When the whole image is read in, we can mark
it as 'complete'. If some time the cluster crashes, the
complete image would help the VMs on the very node to survive
the crash. The dirty bits will be flushed into cluster store
in recovery stage.<br>
<br>
</blockquote>
<div>read-ahead whole image into memory? </div>
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<br>
Into file in the local disk, that is supposed to be mmapped into
qemu process memory.<br>
<br>
Thanks,<br>
Yuan<br>
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