[ovirt-users] Maximum VM memory

[Christophe TREFOIS]

Hi Omer,

Especially the last point of your response is a good thing!

I came across the problem as well, when trying to increase a VM to be > 16 GB and by choosing any other 64 bit template it worked.

Looking forward to these changes,

--
Christophe

-----Original Message-----
From: Omer Frenkel [mailto:ofrenkel at redhat.com] 
Sent: dimanche, le 10 mai 2015 14:59
To: Christophe TREFOIS
Cc: users at ovirt.org
Subject: Re: [ovirt-users] Maximum VM memory



----- Original Message -----
> From: "Christophe TREFOIS" <christophe.trefois at uni.lu>
> To: users at ovirt.org
> Sent: Sunday, May 10, 2015 3:17:12 PM
> Subject: [ovirt-users] Maximum VM memory
> 
> Dear ovirt users,
> 
> We have a special machine which has 1 TB RAM.
> 
> The idea is to have 3-4 VMs on there which should be split like 
> 85/5/5/5 % of total RAM.
> 
> I have three questions:
> 
> 1. Is there any reason not to put up a VM with so much RAM
> 

i don't think there is a problem with that

> 2. How can I increase the maximum RAM size for 64 bit VMs?
> 

i dont think you need to increase the maximum, max ram for 64bit os should be ok for your case with any cluster with compatibility of 3.1 and above (2TiB):
$ engine-config --get VM64BitMaxMemorySizeInMB
VM64BitMaxMemorySizeInMB: 524288 version: 3.0
VM64BitMaxMemorySizeInMB: 2097152 version: 3.1
VM64BitMaxMemorySizeInMB: 2097152 version: 3.2
VM64BitMaxMemorySizeInMB: 2097152 version: 3.3
VM64BitMaxMemorySizeInMB: 4096000 version: 3.4
VM64BitMaxMemorySizeInMB: 4096000 version: 3.5
VM64BitMaxMemorySizeInMB: 4194304 version: 3.6

> 3. How can I create a new OS for the VM creation that supports > 16 GB ?
> (Right now i have to choose RHEL 64 bits even for Debian systems)
> 

please see [1] for customizing guest os information.
please note this bug [2]:
Bug 1218531 - Setting "Other OS" is default 32bit instead of 64bit and causes incorrect RAM size limit of 16GB for 64bit OS. 

should be part of ovirt 3.5.3 where the we change most OS to be 64bit by default so most linux distros will be considered 64bit (Linux, debian 7, suse, ubuntu..)

[1] http://www.ovirt.org/OS_info#value_overriding
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1218531
 
> Thank you for your help,
> 
> —
> Christophe
> 
> 
> 
> 
> 
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