10:39 a.m.
I think that if you run VMs with Databases, you must disable transparent huge pages on
Hypervisour level and on VM level. Yet, if you wish you can use regular huge pages on VM
level.
Best Regards,
Strahil Nikolov
В вторник, 28 септември 2021 г., 09:21:09 ч. Гринуич+3, Tommy Sway
<sz_cuitao(a)163.com> написа:
What problem will appear if I use the default transparent huge page enabled mode for
physical hosts, but configure traditional huge page memory on the virtual machine for
database SGA ?
Or is it better to disable transparent huge page on physical machines and still use
traditional huge page memory on virtual machines?
Which one is prefer ?
From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org> On Behalf Of Strahil Nikolov
via Users
Sent: Tuesday, September 28, 2021 12:05 AM
To: tommy <sz_cuitao(a)163.com>; 'users' <users(a)ovirt.org>
Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit
https://docs.oracle.com/en/database/oracle/oracle-database/19/ladbi/disab...
https://access.redhat.com/solutions/1320153 (requires RH dev subscription or other type of
subscription) -> In short add 'transparent_hugepage=never' to the kernel
params
SLES11/12/15 -> https://www.suse.com/c/sles-1112-os-tuning-optimisation-guide-part-1/
Best Regards,
Strahil Nikolov
> On Mon, Sep 27, 2021 at 16:33, tommy
> <sz_cuitao(a)163.com> wrote:
> thank you!
>
> and how to get the config info of Transparent huge pages and how to disable it？
>
>
>
>
>
> 发自我的华为手机
>
>
> -------- 原始邮件 --------
> 发件人： Strahil Nikolov <hunter86_bg(a)yahoo.com>
> 日期： 2021年9月27日周一 21:13
> 收件人： 'users' <users(a)ovirt.org>, Tommy Sway <sz_cuitao(a)163.com>
> 主 题： Re: [ovirt-users] Re: About the vm memory limit
>> Transparent huge pages are enabled by default, so you need to stop them.I would
use huge pages on both host and VM, but theoretically it shouldn't be a problem
running a VM with enabled HugePages without configuring on Host.Best Regards,Strahil
NikolovВ събота, 25 септември 2021 г., 15:25:10 ч. Гринуич+3, Tommy Sway
<sz_cuitao(a)163.com> написа: transparent huge pages are not used on vm and physical
host. But, can I enable hugepage memory on virtual machines but not on a physical
machine?For database running on vm, and it needs to config hugepage. From: Strahil
Nikolov <hunter86_bg(a)yahoo.com> Sent: Saturday, September 25, 2021 5:32 PMTo: Tommy
Sway <sz_cuitao(a)163.com>Subject: Re: [ovirt-users] About the vm memory limit It
depends on the numa configuration of the host. If you have 256G per CPU, it's best to
stay into that range. Also, consider disabling transparent huge pages on the host &
VM. Since 4.4 Regular Huge Pages (do not confuse them with THP) can be used on the
Hypervisors, while on 4.3 there were some issues but I can't provode any details. Best
Regards,Strahil Nikolov> On Fri, Sep 24, 2021 at 6:40, Tommy Sway>
<sz_cuitao(a)163.com> wrote:> I would like to ask if there is any limit on the
memory size of virtual machines, or performance curve or something like that?> As long
as there is memory on the physical machine, the more virtual machines the better?>
> In our usage scenario, there are many virtual machines with databases, and their
memory varies greatly. > For some virtual machines, 4G memory is enough, while for some
virtual machines, 64GB memory is needed.> > I want to know what is the best use of
memory for a virtual machine, since the virtual machine is just a QEMU emulation process
on a physical machine, and I worry that it is not using as much memory as a physical
machine. Understand this so that we can develop guidelines for optimal memory usage
scenarios for virtual machines.> > Thank you!> > >
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