Bug 1299501

Summary:	[Docs] Memory Usage of ReplicationWorker and evm:dbsync:replicate exceeds Replication Worker Memory Threshold
Product:	Red Hat CloudForms Management Engine	Reporter:	Alex Krzos <akrzos>
Component:	Documentation	Assignee:	Suyog Sainkar <ssainkar>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Red Hat CloudForms Documentation <cloudforms-docs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	5.5.0	CC:	adahms, akrzos, jhardy, mfeifer, obarenbo
Target Milestone:	GA
Target Release:	5.5.3
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	doc
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-01-19 03:49:58 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:

Description Alex Krzos 2016-01-18 14:17:49 UTC

Description of problem:
The Replication Worker spawns a subprocess (evm:dbsync:replicate) that alone can exceed the memory threshold that is permitted by default for the Replication Worker (200MiB by Default).  This process is currently not counted against the Replication Worker Memory threshold.  This can lead administrators to believe a Replication Workload should only consume an amount of memory below the Replication Worker Threshold.

For 5.5.2.0 during stress tests that have lasted around 4 hours.  I have witnessed the following Memory usages:
MiqReplicationWorker - 175-176MiB RSS, 168-170MiB PSS
evm:dbsync:replicate - 206-211MiB RSS, 199-204MiB PSS

For a combined Replication Workload using 381-388MiB RSS

When viewing the processes PSS (Proportional Set Size):
MiqReplicationWorker - 168-170MiB PSS
evm:dbsync:replicate - 199-204MiB PSS

Version-Release number of selected component (if applicable):
5.5.2.0

How reproducible:
Exposed in all tests against 5.5.2.0

Steps to Reproduce:
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Actual results:


Expected results:


Additional info:

Comment 2 dmetzger 2016-02-23 14:53:59 UTC

I'm converting this to a documentation issue to ensure the need to account for approximately 200Mb of additional memory (beyond the amount configured for the MiqReplicationWorker) is accounted for in during configuration planning.

Another possible action would be to include a one line note with the Replication Worker configuration text indicating an additional 200Mb of system memory will be consumed by replication - beyond the configurable worker amount.

Comment 3 Andrew Dahms 2016-02-24 14:10:46 UTC

Assigning to Suyog for review.