Revision: 9a186e675173
Author: riba <[email protected]>
Date: Tue Sep 9 11:15:49 2014 UTC
Log: Edited wiki page PerformanceTuning through web user interface.
https://code.google.com/p/ganeti/source/detail?r=9a186e675173&repo=wiki
Modified:
/PerformanceTuning.wiki
=======================================
--- /PerformanceTuning.wiki Mon Oct 29 13:50:44 2012 UTC
+++ /PerformanceTuning.wiki Tue Sep 9 11:15:49 2014 UTC
@@ -9,23 +9,23 @@
= KVM =
-== cpu -host ==
-ganeti should pass the -cpu host flag to kvm as to optimally use all cpu
features? Issue 159 was filed to that end.
-In the mean time, this can be optained through a wrapper script. Following
procedure is Debian/Ubuntu specific.
+== Host CPU ==
+
+Passes the Host CPU through to the VM, allowing the VM to use all the
+features the host CPU has, speeding up certain workloads (like using
aes-ni for faster crypto).
{{{
-dpkg-divert --add --rename --divert /usr/bin/kvm.real /usr/bin/kvm
-cat <<EOF > /usr/bin/kvm
-#!/bin/sh
-exec /usr/bin/kvm.real -cpu host "\$@"
-EOF
-chmod +x /usr/bin/kvm
+ gnt-cluster modify -H kvm:cpu_type=host # entire cluster
+ gnt-node modify -H kvm:cpu_type=host [node] # single node
+ gnt-instance modify -H cpu_type=host [vm] # single VM
}}}
+
+In case that your cluster has nodes with different CPUs, note that a live
migration between two different CPU types could crash the instance. Ganeti
will not warn you about this at the moment, so you will have to handle the
migrations between such nodes yourself. Although Ganeti could provide
support for this in the future, it does not at the moment. See issue <a
href="https://code.google.com/p/ganeti/issues/detail?id=895";>895</a>.
= DRBD =
See also Issue 57
-== latency tuning =
+== latency tuning ==
As per http://www.drbd.org/users-guide/s-latency-tuning.html :
# use a dedicated nic for DRBD replication and configure jumbo frames:
set the mtu on that interface as high as possible 7200-9000 -
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