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<div class="moz-cite-prefix">Mathok :<br>
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cite="mid:CA+vKXs-1R_Ux8zao7CMO8N_wbejrCWTpr03xzZS6uUcTB1=fWg@mail.gmail.com"
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<div class="gmail_quote">2012/10/17 Alan Johnson <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:alan@datdec.com"
target="_blank">alan@datdec.com</a>></span><br>
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<div class="im">On Wed, Oct 17, 2012 at 5:02 PM, Mathok <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:mathok1@googlemail.com" target="_blank">mathok1@googlemail.com</a>></span>
wrote:<br>
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<div class="im">
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<div>Same here with ovirt 3.1.0-2 i can't see a change
in the UI. But i'm able to start more VMs and hava a
higher usag of my swap partiotion so i think the
change had the desired effect</div>
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<div>Oh, does this take advantage of host swap space as
well? I thought I had read oVirt could do that somewhere,
but I have been reading about so many different
virtualization systems over the last few months that when
the <a moz-do-not-send="true"
href="https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Virtualization/3.1-Beta/html-single/Administration_Guide/index.html"
target="_blank">RHEV 3.1 Admin Guide</a> did not mention
swap space in section "4.2.2.2. Memory Optimization
Settings Explained", I was not sure if it applied here.
This is all it says at the moment:</div>
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<div class="gmail_quote">
<div>"Memory page sharing allows virtual machines to use
up to 200% of their allocated memory by utilizing unused
memory in other virtual machines. This process is based
on the assumption that the virtual machines in your Red
Hat Enterprise Virtualization environment will not all
be running at full capacity at the same time, allowing
unused memory to be temporarily allocated to a
particular virtual machine."</div>
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<div><br>
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<div>Do you have a reference handy that confirms and
explains this? I put some speedy SSDs in my hosts to
hopefully take advantage of this (and maybe run gluster),
so I am hoping to see that in print somewhere. I'll dig
it up if you don't have it handy, but a confirmation that
this is your experience and understanding would make me
feel better in the mean time.</div>
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<div><br>
let me explain my (now fixed) problem i have a ovirt host with
8 GB Ram and 12 VMs every with 256 MB Physical Memory
Guarantee. When i start my two mysql-cluster vms they will use
the 256 PMG plus 3,75 GB MS they have defined a max of 4 GB
MS. At this poitn now the problem begins the mysql taken the
hole memory in both vms and now there is no more free ram at
the host and it is not possible to start more vms. <br>
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<br>
In my understanding, you need to hard cap the physical memory used
by the cluster VM. That will make sure all of the physical memory
used by the VM will not exceed the cap, say 2G. In total, the two
cluster VMs will use 4G memory at most, then the host will have 4G
memory at least to start other VMs. Is that what you want?<br>
<br>
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<blockquote
cite="mid:CA+vKXs-1R_Ux8zao7CMO8N_wbejrCWTpr03xzZS6uUcTB1=fWg@mail.gmail.com"
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<div class="gmail_quote">
<div><br>
(this is also speculation im not a expert) So i need for my
understanding a higher rate of memory overcommit to be able to
start all vms, and for that the host must use the swap to have
enough memory for overcomit to start all vms and yes the
higher the rate, the worse the performance. I'm not sure if
this is the right or good way tho fix this problem<br>
<br>
(sorry for my bad english I hope this is understandable) <br>
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<pre wrap="">_______________________________________________
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</pre>
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<pre class="moz-signature" cols="72">--
---
舒明 Shu Ming
Open Virtualization Engineerning; CSTL, IBM Corp.
Tel: 86-10-82451626 Tieline: 9051626 E-mail: <a class="moz-txt-link-abbreviated" href="mailto:shuming@cn.ibm.com">shuming@cn.ibm.com</a> or <a class="moz-txt-link-abbreviated" href="mailto:shuming@linux.vnet.ibm.com">shuming@linux.vnet.ibm.com</a>
Address: 3/F Ring Building, ZhongGuanCun Software Park, Haidian District, Beijing 100193, PRC</pre>
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