Bug 202760

Summary:	sysctl values too small for larger servers
Product:	Red Hat Enterprise Linux 4	Reporter:	Alexander Hass <alexander.hass>
Component:	kernel	Assignee:	Larry Woodman <lwoodman>
Status:	CLOSED WONTFIX	QA Contact:	Brian Brock <bbrock>
Severity:	low	Docs Contact:
Priority:	medium
Version:	4.2	CC:	fdanapfe, jbaron, linux, nphilipp
Target Milestone:	---	Keywords:	Reopened
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-07-18 08:54:32 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:
Bug Depends On:
Bug Blocks:	219685

Description Alexander Hass 2006-08-16 11:52:38 UTC

The Linux Kernel defaults of the following sysctl parameters are too small to
run larger applications. Values are taken from a server with 8 CPUs and 8 GB
RAM, running RHEL 4 AS Update 2, Kernel 2.6.9-22.0.2.ELsmp x86_64, assuming this
hasn't been changed yet:

1 # cat /proc/sys/kernel/shmmax
33554432 (32 MB)
2 # cat /proc/sys/kernel/shmall
2097152 (8 GB)
3 # cat /proc/sys/kernel/sem
250     32000   32      128

ad 1 and 2) We currently recommend values representing 20 GB each. My proposal
for new default values would be to dynamically adapt them to the available size
of virtual memory, by adding up RAM and Swap.

ad 3) There we recommend our customers to set 1250 256000 100 8192. Is there
also a possibility to adapt a new Kernel default dynamically to larger machines?

If you can't adapt the Kernel defaults, which values would you recommend to
cover even large machines? Think of something with 8 or more CPUs and 64 or more
GB of RAM...

Comment 1 Russell Doty 2007-12-18 20:49:49 UTC

SAP - can you verify that this is still an issue in RHEL 4.6?

Comment 2 Alexander Hass 2008-01-03 17:27:57 UTC

Well, I haven't got any feedback yet from your side...

ad 1 and 2) In the meanwhile you increased those values on RHEL 5; nevertheless
on RHEL 4 the values are still too low.

ad 3) This question is still open

Comment 3 Larry Woodman 2008-11-11 15:31:15 UTC

We cant make this kind of change to RHEL4 this late in the lifecycle.

Larry Woodman

Comment 4 Alexander Hass 2008-11-11 15:59:23 UTC

Well, then why don't you fix it two years ago...
There were also some questions asked, which still haven't been answered by Red Hat yet.

Comment 5 Frank Danapfel 2011-07-18 08:54:32 UTC

RHEL4 is near the end of its lifecycle and on current RHEL5 and RHEL6 releases the default sysctl values are set to much higher values. Therefore I'm closing this bug.