1:15 a.m.
2012/10/17 Alan Johnson <alan(a)datdec.com>
On Wed, Oct 17, 2012 at 5:02 PM, Mathok
<mathok1(a)googlemail.com> wrote:
> 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
>
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 RHEV
3.1 Admin
Guide<https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterpris...
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:
"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."
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.
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.
(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
(sorry for my bad english I hope this is understandable)
1:40 a.m.
New subject: [Users] Ovirt Memory Page Sharing or to less memory
2012/10/18 Mathok <mathok1(a)googlemail.com>
2012/10/17 Alan Johnson <alan(a)datdec.com>
> On Wed, Oct 17, 2012 at 5:02 PM, Mathok <mathok1(a)googlemail.com> wrote:
>
>> 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
>>
>
> 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 RHEV
> 3.1 Admin
Guide<https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterpris...
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:
>
> "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."
>
>
> 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.
>
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.
(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
(sorry for my bad english I hope this is understandable)
sorry i have no reference handy that confirm or explain this for ovirt. i
have only
combined my linux and vmware knowledge and i think that it will
work in ovirt a almost equal way like vmware
http://www.yellow-bricks.com/2011/08/18/swap-to-host-cache-aka-swap-to-ss...
you can speed up the swap in a overcomit situation wit a ssd. On
linux we can simply put the swap on a ssd and we have a very fast swap.
9:34 a.m.
New subject: [Users] Ovirt Memory Page Sharing or to less memory
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Mathok :
2012/10/17 Alan Johnson <alan(a)datdec.com <mailto:alan@datdec.com>>
On Wed, Oct 17, 2012 at 5:02 PM, Mathok <mathok1(a)googlemail.com
<mailto:mathok1@googlemail.com>> wrote:
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
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 RHEV 3.1 Admin Guide
<https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Virtual...
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:
"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."
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.
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.
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?
(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
(sorry for my bad english I hope this is understandable)
_______________________________________________
Users mailing list
Users(a)ovirt.org
http://lists.ovirt.org/mailman/listinfo/users
--
---
?? Shu Ming
Open Virtualization Engineerning; CSTL, IBM Corp.
Tel: 86-10-82451626 Tieline: 9051626 E-mail: shuming(a)cn.ibm.com or
shuming(a)linux.vnet.ibm.com
Address: 3/F Ring Building, ZhongGuanCun Software Park, Haidian District, Beijing 100193,
PRC
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<div class="moz-cite-prefix">Mathok :<br>
</div>
<blockquote
cite="mid:CA+vKXs-1R_Ux8zao7CMO8N_wbejrCWTpr03xzZS6uUcTB1=fWg@mail.gmail.com"
type="cite"><br>
<br>
<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(a)datdec.com</a>&gt;</span><br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<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(a)googlemail.com</a>&gt;</span>
wrote:<br>
</div>
<div class="gmail_quote">
<div class="im">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<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>
</div>
</blockquote>
<div><br>
</div>
</div>
<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_Enterpr...
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>
</div>
<blockquote style="margin:0 0 0 40px;border:none;padding:0px">
<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>
</div>
</blockquote>
<div class="gmail_quote">
<div><br>
</div>
<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>
</div>
</blockquote>
<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>
</div>
</div>
</blockquote>
<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>
<br>
<blockquote
cite="mid:CA+vKXs-1R_Ux8zao7CMO8N_wbejrCWTpr03xzZS6uUcTB1=fWg@mail.gmail.com"
type="cite">
<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>
</div>
</div>
<br>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Users mailing list
<a class="moz-txt-link-abbreviated"
href="mailto:Users@ovirt.org">Users@ovirt.org</a>
<a class="moz-txt-link-freetext"
href="http://lists.ovirt.org/mailman/listinfo/users">http://...
</pre>
</blockquote>
<br>
<br>
<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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