FWN/Beats/Virtualization: Difference between revisions

Latest revision as of 18:09, 18 December 2009

Virtualization

In this section, we cover discussion of Fedora virtualization technologies on the @fedora-virt list.

Contributing Writer: Dale Bewley

Fedora Virtualization List

This section contains the discussion happening on the fedora-virt list.

Virt Status Report

Justin Forbes posted^[1] a Fedora virtualization status report. Justin pointed out F13 bugs^[2] now include Important and Pony classifications in addition to Blocker and Target.

↑ http://www.redhat.com/archives/fedora-virt/2009-December/msg00056.html
↑ http://fedoraproject.org/wiki/Virtualization_bugs

RHEL and Fedora Virtualization Feature Parity

Robert Day wondered how the virtualization features^[1] of Red Hat Enterprise Linux 5.4 compared to Fedora 12.

Daniel Berrange explained^[2] "The KVM based virtualization in RHEL-5.4 is not nearly so far behind Fedora as you might think. The libvirt mgmt stack in RHEL-5.4 was rebased to be near parity with Fedora 11, and KVM in RHEL-5.4 is also pretty close to that using what's best described as a hybrid of kvm-83 and kvm-84."

↑ http://www.redhat.com/virtualization/rhev/
↑ http://www.redhat.com/archives/fedora-virt/2009-December/msg00040.html

@@ Line 1: / Line 1: @@
 [[Category:Virtualization]] <!-- do not copy into FWN issue -->
+{{Anchor|Virtualization}}
-{{Anchor|Virtualization}}
 == Virtualization ==
 In this section, we cover discussion of Fedora virtualization technologies on the
-@fedora-virt and @virt-tools lists..
+@fedora-virt list.
 Contributing Writer: [[User:Dale | Dale Bewley]]
@@ Line 14: / Line 14: @@
 [http://www.redhat.com/mailman/listinfo/fedora-virt fedora-virt list].
-==== KSM Tuning in Fedora 12 ====
+==== Virt Status Report ====
-[[MarkMcLoughlin|Mark McLoughlin]]
+[[JustinForbes|Justin Forbes]]
-described<ref>http://www.redhat.com/archives/fedora-virt/2009-October/msg00119.html</ref>
+posted<ref>http://www.redhat.com/archives/fedora-virt/2009-December/msg00056.html</ref> a Fedora virtualization status report.
-the default state of KSM<ref>http://fedoraproject.org/wiki/Features/KSM</ref> on Fedora systems.
+Justin pointed out F13 bugs<ref>http://fedoraproject.org/wiki/Virtualization_bugs</ref> now include Important and Pony classifications in addition to Blocker and Target.
-"For Fedora 13, it'll be off by default in the kernel and the recommended
-way of switching it on is with 'chkconfig ksm on'"
-"For Fedora [[Releases/12|12]], it's on by default in the kernel, 'chkconfig ksm on' just changes max pages and the only way of disabling it is by manually
-writing zero to {{filename|/sys/kernel/mm/ksm/run}}."
-At release of Fedora 12 the kernel will default to a maximum of 2000 merged memory pages. A future F12 kernel update to 2.6.32 will likely disable KSM by default.
+<references />
-To take advantage of KSM in Fedora 12, the <code>ksm</code> service must be enabled:
-<pre>
-sudo chkconfig ksm on
-</pre>
-[[MarkMcLoughlin|Mark McLoughlin]]
+==== RHEL and Fedora Virtualization Feature Parity ====
-also noted<ref>http://www.redhat.com/archives/fedora-virt/2009-October/msg00112.html</ref>
+Robert Day wondered how the virtualization features<ref>http://www.redhat.com/virtualization/rhev/</ref> of Red Hat Enterprise Linux 5.4
-The maximum number of pages which may be merged defaults to half of the system
+compared to Fedora 12.
-memory, and may also be manually defined in {{filename|/etc/sysconfig/ksm}}.
-"Here's the logic we have in the init script<ref>http://gitorious.org/ksm-control-scripts/ksm-control-scripts</ref>:"
-<pre>
-  # unless KSM_MAX_KERNEL_PAGES is set, let ksm munch up to half of total memory.
-  default_max_kernel_pages () {
-      local total pagesize
-      total=`awk '/^MemTotal:/ {print $2}' /proc/meminfo`
-      pagesize=`getconf PAGESIZE`
-      echo $[total * 1024 / pagesize / 2]
-  }
-</pre>
-[[JustinForbes|Justin Forbes]]
+[[DanielBerrange|Daniel Berrange]]
-points out<ref>http://www.redhat.com/archives/fedora-virt/2009-October/msg00115.html</ref>
+explained<ref>http://www.redhat.com/archives/fedora-virt/2009-December/msg00040.html</ref>
-"The limit to half of total memory is because ksm pages are unswappable at
+"The KVM based virtualization in RHEL-5.4 is not nearly so far behind
-this time.  To be fixed in a future kernel."
+Fedora as you might think. The {{package|libvirt}} mgmt stack in RHEL-5.4 was
+rebased to be near parity with [[Releases/11|Fedora 11]], and KVM in RHEL-5.4 is
+also pretty close to that using what's best described as a hybrid of
+kvm-83 and kvm-84."
+<references />
-A second service, <code>ksmtuned</code>, may also be enabled.
-Ksmtuned regulates how aggressively the system will attempt to merge pages.
-Parameters such as how many pages to scan before sleeping and how long to
-sleep may be configured in {{filename|/etc/ksmtuned.conf}}.
-Memory pages must be flagged as mergable before KSM will scan them looking for
+====  ====
-duplicates. At present only Qemu pages will be marked as such.
+<references />
-As described in the kernel docs<ref>http://www.kernel.org/doc/Documentation/vm/ksm.txt</ref>,
-the effect of KSM system memory may be examined in {{filename|/sys/kernel/mm/ksm}}.
-"A high ratio of pages_sharing to pages_shared indicates good sharing, but
-a high ratio of pages_unshared to pages_sharing indicates wasted effort."
+====  ====
 <references />

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