Bug 311751

Summary:	host has 194 LUNs and each LUNs has 15 partitions now. Start with PowerPath also cause the server hang.
Product:	Red Hat Enterprise Linux 4	Reporter:	Pan Haifeng <pan_haifeng>
Component:	udev	Assignee:	Harald Hoyer <harald>
Status:	CLOSED WONTFIX	QA Contact:	qe-baseos-daemons
Severity:	high	Docs Contact:
Priority:	low
Version:	4.5	CC:	eldesoky
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2012-06-20 15:55:33 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Pan Haifeng 2007-09-28 21:16:13 UTC

Description of problem:

In such configuration, during powerpath start, after PP has presented the
native and pseudo devices to the Linux kernel, udev and hotplug systems
trigger thousands events and each of this event spawns a udev and hotplug
process. In this transient system state, the server has more then 5000
hotplug processes  and around 3000 udev processes. [ Hotplug and udev
processes present currently available devices to the /dev directory.]. It
takes a long time for these processes to finish, because the partition
events have to wait for the main block device event so the partition event
can import the parents information, already stored in the udev database.
The performance consequences of this to the server can be summarized in a
single word - catastrophe

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Comment 1 Jiri Pallich 2012-06-20 15:55:33 UTC

Thank you for submitting this issue for consideration in Red Hat Enterprise Linux. The release for which you requested us to review is now End of Life. 
Please See https://access.redhat.com/support/policy/updates/errata/

If you would like Red Hat to re-consider your feature request for an active release, please re-open the request via appropriate support channels and provide additional supporting details about the importance of this issue.