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 Nikolov В събота, 25 септември 2021 г., 15:25:10 ч. Гринуич+3, Tommy Sway <sz_cuitao(a)163.com&gt; 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&gt; Sent: Saturday, September 25, 2021 5:32 PMTo: Tommy Sway <sz_cuitao(a)163.com&gt;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 _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/3YHTUBAG42Y...

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&lt;sz_cuitao(a)163.com&gt; 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&gt; 日期： 2021年9月27日周一 21:13 收件人： 'users' <users(a)ovirt.org&gt;, Tommy Sway <sz_cuitao(a)163.com&gt; 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 Nikolov В събота, 25 септември 2021 г., 15:25:10 ч. Гринуич+3, Tommy Sway <sz_cuitao(a)163.com&gt; 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&gt; Sent: Saturday, September 25, 2021 5:32 PMTo: Tommy Sway <sz_cuitao(a)163.com&gt;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 _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/3YHTUBAG42Y...

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&gt; 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&gt; 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&gt; 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&gt; 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&gt; > 日期： 2021年9月27日周一 21:13 > 收件人： 'users' <users(a)ovirt.org&gt;, Tommy Sway <sz_cuitao(a)163.com&gt; > 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&gt; 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&gt; Sent: Saturday, September 25, 2021 5:32 PMTo: Tommy Sway <sz_cuitao(a)163.com&gt;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&gt; 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!>  >  > _______________________________________________Users mailing list -- users(a)ovirt.orgTo unsubscribe send an email to users-leave(a)ovirt.orgPrivacy Statement: https://www.ovirt.org/privacy-policy.htmloVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/Y6XDOIMKCP4... mailing list -- users(a)ovirt.orgTo unsubscribe send an email to users-leave(a)ovirt.orgPrivacy Statement: https://www.ovirt.org/privacy-policy.htmloVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/3YHTUBAG42Y...

If you are on 4.3 -> disable transparent hugepages both Hypervisor and VM.If you are using 4.4 -> disable transparent hugepages and also cobfigure regular huge pages. Best Regards,Strahil Nikolov On Wed, Sep 29, 2021 at 5:34, Tommy Sway&lt;sz_cuitao(a)163.com&gt; wrote: From the Oracle OLVM support: Configuring the Hugepages for guest VMs should be suffice, however, it needs the KVM hosts too configured with the Hugepages. Since, if it not you may end with issues while staring the guest VMs. I really don't know what to do now. -----Original Message----- From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of Strahil Nikolov via Users Sent: Tuesday, September 28, 2021 3:39 PM To: 'users' <users(a)ovirt.org>; Tommy Sway <sz_cuitao(a)163.com&gt; Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit 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&gt; 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&gt; 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&gt; 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 _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/GRNMITHSDUE... _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/QBQHER4G2VL...

I got a 3 TB host (physical) with Oracle without Traditional Hugepages. The DB will work even without hugepages... but how much memory will be lost - that's another story. Disable the transparent Huge Pages and check this documentation - should be valid for oVirt 4.3 and OLVM 4.3 as they share the same source: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.3/... Best Regards, Strahil Nikolov В сряда, 29 септември 2021 г., 15:20:54 ч. Гринуич+3, Tommy Sway <sz_cuitao(a)163.com&gt; написа: I’am 4.3, but the memory of the VM and the SGA is large , 32GB, so the vm should set the traditional hugepage for the database SGA.   I don't know how to set up a large page on a KVM host. Because if I make it a traditional big page, how big should I make it? Will non-VM SGA usage of many VMs be affected? After all, not all memory used by QEMU needs to be HugePage, and traditional large page memory needs to be used by specific code calls and is not transparent.   These are all questions.         From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of Strahil Nikolov via Users Sent: Wednesday, September 29, 2021 5:39 PM To: Tommy Sway <sz_cuitao(a)163.com>; 'users' <users(a)ovirt.org&gt; Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit   If you are on 4.3 -> disable transparent hugepages both Hypervisor and VM. If you are using 4.4 -> disable transparent hugepages and also cobfigure regular huge pages.   Best Regards, Strahil Nikolov > On Wed, Sep 29, 2021 at 5:34, Tommy Sway > <sz_cuitao(a)163.com&gt; wrote: > From the Oracle OLVM support: > > Configuring the Hugepages for guest VMs should be suffice, however, it needs the KVM hosts too configured with the Hugepages. > Since, if it not you may end with issues while staring the guest VMs. > > I really don't know what to do now. > > > > > > -----Original Message----- > From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of Strahil Nikolov via Users > Sent: Tuesday, September 28, 2021 3:39 PM > To: 'users' <users(a)ovirt.org>; Tommy Sway <sz_cuitao(a)163.com&gt; > Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit > > 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&gt; 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&gt; 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&gt; > 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&gt; 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&gt; >> 日期： 2021年9月27日周一 21:13 >> 收件人： 'users' <users(a)ovirt.org&gt;, Tommy Sway <sz_cuitao(a)163.com&gt; >> 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&gt; 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&gt; Sent: Saturday, September 25, 2021 5:32 PMTo: >> Tommy Sway <sz_cuitao(a)163.com&gt;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&gt; 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!>  >  > >> _______________________________________________Users mailing list -- >> users(a)ovirt.orgTo unsubscribe send an email to >> users-leave(a)ovirt.orgPrivacy Statement: >> https://www.ovirt.org/privacy-policy.htmloVirt Code of Conduct: >> https://www.ovirt.org/community/about/community-guidelines/List >> Archives: >> https://lists.ovirt.org/archives/list/users@ovirt.org/message/Y6XDOIM>... KCP4JEJF7M5DLJ33U2ENJKGAN/___________________________________________>> ____Users mailing list -- users(a)ovirt.orgTo unsubscribe send an email >> to users-leave(a)ovirt.orgPrivacy Statement: >> https://www.ovirt.org/privacy-policy.htmloVirt Code of Conduct: >> https://www.ovirt.org/community/about/community-guidelines/List >> Archives: >> https://lists.ovirt.org/archives/list/users@ovirt.org/message/3YHTUBA>... G42YRNEUCWG4DF5TEP2I22DMH/_______________________________________________Users mailing list -- users(a)ovirt.orgTo unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.htmloVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/GRNMITHSDUE... > _______________________________________________Users mailing list -- users(a)ovirt.orgTo unsubscribe send an email to users-leave(a)ovirt.orgPrivacy Statement: https://www.ovirt.org/privacy-policy.htmloVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/List Archives: > https://lists.ovirt.org/archives/list/users@ovirt.org/message/QBQHER4G2VL... >   

Each VM for that 4TB host will be a single process. When that process addresses some memory location, the kernel will lookup in the translation lookaside buffer (TLB) and in case the Host is using Hugepages the kernel needs less time to find the memory page (page table walk), which slows the process (in your case the VM). Simplified said -> the VM process should be seen as an Oracle DB. On bare metal you want to disable transparent hugepages and enable the 2M hugepages for ODB - so logically VMs doing the same workload should be treated the same way. Here is a link to Oracle's OLVM (based on oVirt): https://docs.oracle.com/en/virtualization/oracle-linux-virtualization-man... Best Regards,Strahil Nikolov On Thu, Sep 30, 2021 at 6:25, Tommy Sway&lt;sz_cuitao(a)163.com&gt; wrote: In my scenario, the physical machine has a lot of memory (4TB), with dozens of virtual machines running on it, each vm is running a database, and every vm is set up with traditional large-page memory. In this case, whether it is necessary to set up large page memory on the physical machine and what type of large page memory should be set up, this issue has not been determined, I am also very confused. -----Original Message----- From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of Strahil Nikolov via Users Sent: Wednesday, September 29, 2021 8:50 PM To: 'users' <users(a)ovirt.org>; Tommy Sway <sz_cuitao(a)163.com&gt; Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit I got a 3 TB host (physical) with Oracle without Traditional Hugepages. The DB will work even without hugepages... but how much memory will be lost - that's another story. Disable the transparent Huge Pages and check this documentation - should be valid for oVirt 4.3 and OLVM 4.3 as they share the same source: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.3/... Best Regards, Strahil Nikolov В сряда, 29 септември 2021 г., 15:20:54 ч. Гринуич+3, Tommy Sway <sz_cuitao(a)163.com&gt; написа: I’am 4.3, but the memory of the VM and the SGA is large , 32GB, so the vm should set the traditional hugepage for the database SGA. I don't know how to set up a large page on a KVM host. Because if I make it a traditional big page, how big should I make it? Will non-VM SGA usage of many VMs be affected? After all, not all memory used by QEMU needs to be HugePage, and traditional large page memory needs to be used by specific code calls and is not transparent. These are all questions. From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of Strahil Nikolov via Users Sent: Wednesday, September 29, 2021 5:39 PM To: Tommy Sway <sz_cuitao(a)163.com>; 'users' <users(a)ovirt.org&gt; Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit If you are on 4.3 -> disable transparent hugepages both Hypervisor and VM. If you are using 4.4 -> disable transparent hugepages and also cobfigure regular huge pages. Best Regards, Strahil Nikolov _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/XZ7PQ6ZHZP5... _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/5OWROWEV32Q...

Actually yes - should speedup the process. I've edited that draft too many times :) On Fri, Oct 1, 2021 at 7:32, tommy sway&lt;sz_cuitao(a)163.com&gt; wrote: _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/LMPJISCMPKR...

KVM host -> Just enable it. All VMs will be in Hugepages. VM -> just for the SGA. Best Regards,Strahil Nikolov On Fri, Oct 1, 2021 at 18:01, ‪‪‪tommy‬&lt;sz_cuitao(a)163.com&gt; wrote: If both the KVM server and the VIRTUAL machine are configured with traditional large pages, there is also the issue of configuring size. Since only THE SGA uses large pages, other database components cannot use them. Should the KVM server and virtual machine use the same memory ratio for large pages? For example, use 50% of the total memory size to avoid imbalance caused by improper proportion. -------- 原始邮件 -------- 发件人： Strahil Nikolov <hunter86_bg(a)yahoo.com&gt; 日期： 2021年10月1日周五 22:52 收件人： tommy sway <sz_cuitao(a)163.com&gt;, Strahil Nikolov via Users <users(a)ovirt.org&gt; 主 题： Re: [ovirt-users]Re: 回复： Re: About the vm memory limit Actually yes - should speedup the process. I've edited that draft too many times :) On Fri, Oct 1, 2021 at 7:32, tommy sway&lt;sz_cuitao(a)163.com&gt; wrote: _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/LMPJISCMPKR...

If it is transparent huge page, I can only enable it, but the traditional huge page is required to specify the specific size. Should I follow the principle that the size of huge pages on a physical machine equals the sum of the size of huge pages on all VMS running on it? From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of tommy sway Sent: Saturday, October 2, 2021 1:32 PM To: Strahil Nikolov via Users <users(a)ovirt.org&gt; Subject: [ovirt-users]Re: 回复：Re: 回复： Re: About the vm memory limit but config what size of the hugepage on the kvm host？ On 10/02/2021 01:33, <mailto:users@ovirt.org> Strahil Nikolov via Users wrote: KVM host -> Just enable it. All VMs will be in Hugepages. VM -> just for the SGA. Best Regards, Strahil Nikolov On Fri, Oct 1, 2021 at 18:01, ‪‪‪tommy <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> > wrote: If both the KVM server and the VIRTUAL machine are configured with traditional large pages, there is also the issue of configuring size. Since only THE SGA uses large pages, other database components cannot use them. Should the KVM server and virtual machine use the same memory ratio for large pages? For example, use 50% of the total memory size to avoid imbalance caused by improper proportion. -------- 原始邮件 -------- 发件人： Strahil Nikolov <hunter86_bg(a)yahoo.com <mailto:hunter86_bg@yahoo.com> > 日期： 2021年10月1日周五 22:52 收件人： tommy sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> >, Strahil Nikolov via Users <users(a)ovirt.org <mailto:users@ovirt.org> > 主 题： Re: [ovirt-users]Re: 回复： Re: About the vm memory limit Actually yes - should speedup the process. I've edited that draft too many times :) On Fri, Oct 1, 2021 at 7:32, tommy sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> > wrote: _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/LMPJISCMPKR...

Do you mean the best way is to enable traditional hugepage memory only on virtual machines and turn off the default transparent hugepage memory on physical machines and without enabling traditional hugepage memory? On 10/03/2021 04:03, Strahil Nikolov via Users wrote: vdsm supports dynamic allocation of Huge Pages, but https://access.redhat.com/solutions/4904441 indicates the issues in 4.3 related to hugepages (you can see the solution via RH dev subscription). If you needed to set them manually and everything works normally, I would have picked something like 90-95% in HugePages. Yet, due to the issues described in that solution - it's better to enable HugePages only in the Guest. Best Regards, Strahil Nikolov On Sat, Oct 2, 2021 at 10:13, Tommy Sway <sz_cuitao(a)163.com&gt; wrote: _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/CEXZE5QYTWW...

SUBSCRIBER EXCLUSIVE CONTENT An active Red Hat subscription is required to participate. I cannot get the result. From: users-bounces(a)ovirt.org <users-bounces(a)ovirt.org&gt; On Behalf Of Strahil Nikolov via Users Sent: Sunday, October 3, 2021 4:03 AM To: sz_cuitao(a)163.com; 'Strahil Nikolov via Users' <users(a)ovirt.org&gt; Subject: [ovirt-users]Re: 回复：Re: 回复： Re: About the vm memory limit vdsm supports dynamic allocation of Huge Pages, but https://access.redhat.com/solutions/4904441 indicates the issues in 4.3 related to hugepages (you can see the solution via RH dev subscription). If you needed to set them manually and everything works normally, I would have picked something like 90-95% in HugePages. Yet, due to the issues described in that solution - it's better to enable HugePages only in the Guest. Best Regards, Strahil Nikolov On Sat, Oct 2, 2021 at 10:13, Tommy Sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> > wrote: _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/CEXZE5QYTWW...

3.1.4.2 Configuring Huge Pages You can configure a virtual machine for high performance, so that it runs with performance metrics as close to bare metal as possible. When you choose high performance optimization, the virtual machine is configured with a set of automatic and recommended manual settings for maximum efficiency. By using huge pages, you increase the page size which reduces the page table, reduces the pressure on the Translation Lookaside Buffer cache, and improves performance. Huge pages are pre-allocated when a virtual machine starts to run (dynamic allocation is disabled by default). **** Are Virtual machines mentioned here with high performance option ? So they turn off transparent huge pages by default and use traditional huge pages instead ?? **** Most normal virtual machines use large transparent pages by default in their operating systems. Note If you configure huge pages for a virtual machine, you cannot hotplug or hot uplug memory. To configure huge pages: 1. In the Custom Properties tab, select hugepages from the custom properties list, which displays Please select a key…​ by default. 2. Enter the huge page size in KB. You should set the huge page size to the largest size supported by the pinned host. The recommended size for x86_64 is 1 GB. The huge page size has the following requirements: * The virtual machine’s huge page size must be the same size as the pinned host’s huge page size. * The virtual machine’s memory size must fit into the selected size of the pinned host’s free huge pages. * The NUMA node size must be a multiple of the huge page’s selected size. To enable dynamic allocation of huge pages: 1. Disable the HugePages filter in the scheduler. 2. In the [performance] section in /etc/vdsm/vdsm.conf set the following: use_dynamic_hugepages = true **** what kind of hugepage it is ? Tradition Hugepages or Transparent Hugepages ? And it is archived by VDSM ?? **** I’m really get confused. From: Strahil Nikolov <hunter86_bg(a)yahoo.com&gt; Sent: Thursday, September 30, 2021 11:35 PM To: Tommy Sway <sz_cuitao(a)163.com>; 'users' <users(a)ovirt.org&gt; Subject: Re: [ovirt-users]Re: 回复： Re: About the vm memory limit Each VM for that 4TB host will be a single process. When that process addresses some memory location, the kernel will lookup in the translation lookaside buffer (TLB) and in case the Host is using Hugepages the kernel needs less time to find the memory page (page table walk), which slows the process (in your case the VM). Simplified said -> the VM process should be seen as an Oracle DB. On bare metal you want to disable transparent hugepages and enable the 2M hugepages for ODB - so logically VMs doing the same workload should be treated the same way. Here is a link to Oracle's OLVM (based on oVirt): https://docs.oracle.com/en/virtualization/oracle-linux-virtualization-man... Best Regards, Strahil Nikolov On Thu, Sep 30, 2021 at 6:25, Tommy Sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> > wrote: In my scenario, the physical machine has a lot of memory (4TB), with dozens of virtual machines running on it, each vm is running a database, and every vm is set up with traditional large-page memory. In this case, whether it is necessary to set up large page memory on the physical machine and what type of large page memory should be set up, this issue has not been determined, I am also very confused. -----Original Message----- From: users-bounces(a)ovirt.org <mailto:users-bounces@ovirt.org> <users-bounces(a)ovirt.org <mailto:users-bounces@ovirt.org> > On Behalf Of Strahil Nikolov via Users Sent: Wednesday, September 29, 2021 8:50 PM To: 'users' <users(a)ovirt.org <mailto:users@ovirt.org> >; Tommy Sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> > Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit I got a 3 TB host (physical) with Oracle without Traditional Hugepages. The DB will work even without hugepages... but how much memory will be lost - that's another story. Disable the transparent Huge Pages and check this documentation - should be valid for oVirt 4.3 and OLVM 4.3 as they share the same source: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.3/... Best Regards, Strahil Nikolov В сряда, 29 септември 2021 г., 15:20:54 ч. Гринуич+3, Tommy Sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> > написа: I’am 4.3, but the memory of the VM and the SGA is large , 32GB, so the vm should set the traditional hugepage for the database SGA. I don't know how to set up a large page on a KVM host. Because if I make it a traditional big page, how big should I make it? Will non-VM SGA usage of many VMs be affected? After all, not all memory used by QEMU needs to be HugePage, and traditional large page memory needs to be used by specific code calls and is not transparent. These are all questions. From: users-bounces(a)ovirt.org <mailto:users-bounces@ovirt.org> <users-bounces(a)ovirt.org <mailto:users-bounces@ovirt.org> > On Behalf Of Strahil Nikolov via Users Sent: Wednesday, September 29, 2021 5:39 PM To: Tommy Sway <sz_cuitao(a)163.com <mailto:sz_cuitao@163.com> >; 'users' <users(a)ovirt.org <mailto:users@ovirt.org> > Subject: [ovirt-users]Re: 回复： Re: About the vm memory limit If you are on 4.3 -> disable transparent hugepages both Hypervisor and VM. If you are using 4.4 -> disable transparent hugepages and also cobfigure regular huge pages. Best Regards, Strahil Nikolov _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/XZ7PQ6ZHZP5... _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/privacy-policy.html oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/5OWROWEV32Q...