Thanks for your response. Is this mean if I want to create an instance with flavor: 16G memory (hw:mem_page_size=large), I need to preserve memory more than 16GB ? This instance consume hugepages resource.
2017-09-06 1:47 GMT+08:00 Jay Pipes <jaypi...@gmail.com>: > Please remember to add a topic [nova] marker to your subject line. Answer > below. > > On 09/05/2017 04:45 AM, Weichih Lu wrote: > >> Dear all, >> >> I have a compute node with 64GB ram. And I set 50 hugepages wiht 1GB >> hugepage size. I used command "free", it shows free memory is about 12GB. >> And free hugepages is 50. >> > > Correct. By assigning hugepages, you use the memory allocated to the > hugepages. > > Then I launch an instance with 16GB memory, set flavor tag : >> hw:mem_page_size=large. It show Error: No valid host was found. There are >> not enough hosts available. >> > > Right, because you have only 12G of RAM available after > creating/allocating 50G out of your 64G. > > Huge pages are entirely separate from the normal memory that a flavor > consumes. The 16GB memory in your flavor is RAM consumed on the host. The > huge pages are individual things that are consumed by the NUMA topology > that your instance will take. RAM != huge pages. Totally different things. > > And I check nova-scheduler log. My > >> compute is removed by RamFilter. I can launch an instance with 8GB memory >> successfully, or I can launch an instance with 16GB memory sucessfully by >> remove RamFilter. >> > > That's because RamFilter doesn't deal with huge pages. Because huge pages > are a different resource than memory. The page itself is the resource. > > The NUMATopologyFilter is the scheduler filter that evaluates the huge > page resources on a compute host and determines if the there are enough > *pages* available for the instance. Note that I say *pages* because the > unit of resource consumption for huge pages is not MB of RAM. It's a single > memory page. > > Please read this excellent article by Steve Gordon for information on what > NUMA and huge pages are and how to use them in Nova: > > http://redhatstackblog.redhat.com/2015/09/15/driving-in-the- > fast-lane-huge-page-support-in-openstack-compute/ > > Best, > -jay > > Does RamFilter only check free memory but not free hugepages? >> How can I solve this problem? >> >> I use openstack mitaka version. >> >> thanks >> >> WeiChih, Lu. >> >> Best Regards. >> >> >> _______________________________________________ >> Mailing list: http://lists.openstack.org/cgi >> -bin/mailman/listinfo/openstack >> Post to : openstack@lists.openstack.org >> Unsubscribe : http://lists.openstack.org/cgi >> -bin/mailman/listinfo/openstack >> >> > _______________________________________________ > Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstac > k > Post to : openstack@lists.openstack.org > Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstac > k >
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