Bug 919201 – Warning when migration is delayed/get stuck due to high guest memory writes.

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Bug 919201 - Warning when migration is delayed/get stuck due to high guest memory writes.

Summary:	Warning when migration is delayed/get stuck due to high guest memory writes.

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Virtualization Manager
Classification:	Red Hat
Component:	vdsm (Show other bugs)
Sub Component:
Version:	3.1.0
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	3.2.0
Assigned To:	Saveliev Peter
QA Contact:	Tareq Alayan
Docs Contact:

URL:
Whiteboard:	virt
Keywords:	Patch

Depends On:
Blocks:	902971 948448
	Show dependency tree / graph

Reported:	2013-03-07 15:29 EST by Amador Pahim
Modified:	2018-09-07 12:11 EDT (History)
CC List:	12 users (show)

See Also:
Fixed In Version:	vdsm-4.10.2-18.0.el6ev
Doc Type:	Bug Fix
Doc Text:	Previously, VDSM did not distinguish between migration failures caused by high guest-memory writes and migration failures caused by high network load. This meant that it wasn't clear why migrations failed. New error messages in the logs allow users to distinguish between migration failures caused by high guest-memory writes and migration failures caused by high network load.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2013-06-10 16:43:06 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
oVirt gerrit	12557	None	None	None	Never
Red Hat Product Errata	RHSA-2013:0886	normal	SHIPPED_LIVE	Moderate: rhev 3.2 - vdsm security and bug fix update	2013-06-10 20:25:02 EDT

Groups: None (edit)

Description Amador Pahim 2013-03-07 15:29:31 EST

Description of problem:
Migration process consists in copy guest RAM to new Host. After the
copy, migration code loops back to the beginning and re-copies all pages
modified after the copy. The hope is that the list of pages which must
be copied shrinks with each pass over the memory range.
Guests with large number of memory writes can delay migration process
and even stuck it, if memory writes are faster than memory copy.
Currently, vdsm does not differentiate between migration not progressing due to high guest memory changes and due to memory copy hang.

Version-Release number of selected component (if applicable):
vdsm-4.10.2-1.6.el6.x86_64

Expected results:
Print a warning message when migration is not progressing due to high guest memory changes.

Comment 1 Amador Pahim 2013-03-07 15:31:11 EST

Proposed patch:
http://gerrit.ovirt.org/12557

Comment 6 Dan Kenigsberg 2013-03-11 09:49:58 EDT

Why the current state, where the log has

 Migration Progress: %s seconds elapsed, %s%% of data processed ...

and the % of data processed is jumping/stalling, is not enough?

Comment 7 Amador Pahim 2013-03-11 10:27:36 EDT

No. Migration can be stalled for network load, destination host interruptions and so forth. In these cases, dataRemaining will be equal to smallest_dataRemaining. We should be able to identify when migration is not progressing due to high memory changes inside the guest (dataRemaining > smallest_dataRemaining). Btw, after some time trying to migrate in this scenario, the progress was used to go over 100% of data processed, but ffdc10c0 changed the progress to be always less than 100%. Now we can't identify the situation in any case.

Comment 8 Saveliev Peter 2013-03-20 11:23:33 EDT

Was merged as 95789edc988072202787729c3ff4e99ec95afcb6

Comment 15 errata-xmlrpc 2013-06-10 16:43:06 EDT

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

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