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Bug 956683

Summary:	The default migration_max_bandwidth (32MiBps) & default max_outgoing_migrations (5) will saturate a 1Gbps link.
Product:	Red Hat Enterprise Virtualization Manager	Reporter:	Lee Yarwood <lyarwood>
Component:	vdsm	Assignee:	Nobody's working on this, feel free to take it <nobody>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	3.1.3	CC:	abaron, acathrow, bazulay, cpelland, hateya, iheim, lpeer, michal.skrivanek, mpavlik, oramraz, ybronhei, ykaul, zdover
Target Milestone:	---	Keywords:	ZStream
Target Release:	3.2.0
Hardware:	All
OS:	All
Whiteboard:	virt
Fixed In Version:	vdsm-4.10.2-17.0.el6ev	Doc Type:	Bug Fix
Doc Text:	Previously, the default migration_max_bandwith (32MiBps) and the max_outgoing_migrations (5) saturated a 1Gbps link with migration traffic. This left no room for other kinds of traffic (for instance, management traffic). The max_outgoing_migrations default has been changed from 5 to 3. Migrations no longer saturate a 1Gbps link.	Story Points:	---
Clone Of:
Clones:	956724 (view as bug list)		Environment:
Last Closed:	2013-06-10 20:48:51 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	956724

Description Lee Yarwood 2013-04-25 12:37:07 UTC

Description of problem:
The default migration_max_bandwidth (32MiBps) & max_outgoing_migrations (5) will saturate a 1Gbps link.

Version-Release number of selected component (if applicable):
vdsm-4.10.2-16.0.el6ev

How reproducible:
Always.

Steps to Reproduce:
1. Start 5 or more migrations.
2. A typical 1Gbps link will become saturated with migration traffic.
  
Actual results:
1Gbps link saturated.

Expected results:
A 1Gbps link should not become saturated with migration traffic allowing room for management traffic etc.

Additional info:
BZ#925981 reverts vdsm to it's previous default behaviour of 32MiBps per migration but given the number of 5 out going migrations we can still saturate a typical 1Gbps link.

The real fix here is to dynamically calculate the bandwidth and number of migrations given the link speed to the migration network.

Comment 1 Andrew Cathrow 2013-04-25 13:17:01 UTC

So the action is to change the default form 5 to 3 concurrent

Comment 2 Michal Skrivanek 2013-04-25 13:33:55 UTC

target should be 3.2.0, the posted patch 7855 belongs to 3.1.z clone

Comment 4 Michal Skrivanek 2013-04-25 14:12:34 UTC

merged to master:
http://gerrit.ovirt.org/gitweb?p=vdsm.git;a=commit;h=a902734ff87f34b3066972ec47c7806d3acff005

Comment 7 Martin Pavlik 2013-05-02 13:07:30 UTC

works on SF15, max bandwidth usage during migration is approx 96MB/s

Comment 10 errata-xmlrpc 2013-06-10 20:48:51 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-0886.html