Bug 1337228

Summary:	empty ioTune policy is being set periodically even when no QoS is configured at all
Product:	[oVirt] mom	Reporter:	Michal Skrivanek <michal.skrivanek>
Component:	Core	Assignee:	Martin Sivák <msivak>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Shira Maximov <mshira>
Severity:	high	Docs Contact:
Priority:	high
Version:	0.5.1	CC:	bugs, dfediuck, mavital, msivak, rgolan
Target Milestone:	ovirt-3.6.7	Flags:	michal.skrivanek: ovirt-3.6.z? michal.skrivanek: planning_ack? michal.skrivanek: devel_ack+ mavital: testing_ack+
Target Release:	0.5.4
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	mom-0.5.4-1	Doc Type:	Bug Fix
Doc Text:	Cause: MOM was trying to enforce an IO policy even though none was configured or when no change was needed. Consequence: Extra API requests were generated causing higher than necessary load to VDSM. Fix: An update needed condition was added to limit API requests. Result: Lower VDSM API load.	Story Points:	---
Clone Of:
Clones:	1343960 (view as bug list)		Environment:
Last Closed:	2016-07-04 12:31:44 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	SLA	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1337229, 1343960

Description Michal Skrivanek 2016-05-18 14:34:47 UTC

Currently mom issues several calls on per VM basis every 15s. Some of them are not needed, notably setting the iotune policy when nothing is configured in the engine (that's the default)
This has impact on performance in scale environment

Comment 1 Roy Golan 2016-05-19 08:01:06 UTC

(In reply to Michal Skrivanek from comment #0)
> Currently mom issues several calls on per VM basis every 15s. Some of them
> are not needed, notably setting the iotune policy when nothing is configured
> in the engine (that's the default)
> This has impact on performance in scale environment

What's the impact if? you mean calling VDSM I guess and not an empty IOtune which sets something?

Comment 2 Doron Fediuck 2016-05-30 09:23:55 UTC

Is this relevant for 4.0 as well?

Comment 3 Michal Skrivanek 2016-05-30 09:27:16 UTC

Roy, can you please rephrase the question? Impact is a heavy API call every few ms on a busy host.
Doron, yes.

Comment 4 Shira Maximov 2016-06-13 09:56:18 UTC

verified on :
Red Hat Enterprise Virtualization Manager Version: 3.6.7.2-0.1.el6

verification steps:
1. installting mom-0.5.4-1 on 3.6 host (from here: https://brewweb.engineering.redhat.com/brew/buildinfo?buildID=497698)
2. run some VMs with guest agent 
3. check in vdsm logs that logs with the words :vmSetIoTune and vmGetIoTune won't appere 


comment- 
I didn't get mom-0.5.4-1 from the latest build, but downloaded directry from this link: https://brewweb.engineering.redhat.com/brew/buildinfo?buildID=497698)