Bug 722277

Summary:	F15 sysctl fails to set a setting due to missing (or removed) /proc entry (must use rc.local)
Product:	[Fedora] Fedora	Reporter:	Reartes Guillermo <rtguille>
Component:	sysfsutils	Assignee:	Anton Arapov <anton>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	low	Docs Contact:
Priority:	unspecified
Version:	14	CC:	anton, fedora, jcapik, ktdreyer, nobody
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-10-31 09:45:38 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Reartes Guillermo 2011-07-14 20:01:20 UTC

Description of problem:

/dev/sda is a SSD drive, so i tried to change the elevator just for that device (i also have 4 HDDs) and tried to use the sysctl.conf file first (in a fedoraforum ssd thread), so:

# sysctl -a | grep block.sda.queue.scheduler

# cat /sys/block/sda/queue/scheduler
noop deadline [cfq] 

# cat /sys/block/sdb/queue/scheduler
noop deadline [cfq] 

# cat /sys/block/sdc/queue/scheduler
noop deadline [cfq] 

# sysctl -w block.sda.queue.scheduler=noop
/proc/sys/block/sda/queue/scheduler: No such file or directory

So using sysctl to change 'block.sda.queue.scheduler' fails, the file is
not there... Maybe the feature is deprecated, removed or other.

# echo "noop" > /sys/block/sda/queue/scheduler

# cat /sys/block/sda/queue/scheduler
[noop] deadline cfq 

So i ended adding the enty 'echo "noop" > /sys/block/sda/queue/scheduler' to the /etc/rc.d/rc.local which is not as elegant as sysctl.conf


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

procps.x86_64    3.2.8-21.20110302git.fc15     @updates
kernel           2.6.38.8-35.fc15.x86_64

How reproducible:
allways

Steps to Reproduce:
explained above.
  
Actual results:
must use rc.local

Comment 1 Ken Dreyer 2011-08-23 20:49:43 UTC

Also present in RHEL 6.1, procps-3.2.8-17.el6.

Comment 2 Jaromír Cápík 2011-10-27 11:28:16 UTC

Hello guys.

That must be a mistake on the fedoraforum.
AFAIK block.* was never a part of the /proc filesystem.
It's a part of the /sys filesystem.
Debian based distributions configure all /sys related stuff in /etc/sysfs.conf (not /etc/sysctl.conf).
sysfs.conf + initscript is located in the Debian's "sysfsutils" package. Fedora is missing such initscript and config file. You can request this feature in Fedora too, but since it has nothing to do with procps, I'm changing the component to sysfsutils.

Regards,
Jaromir.

Comment 3 Anton Arapov 2011-10-31 09:45:38 UTC

sysfsutils is kind of deprecated and not a way to go to solve such an issue.
Either 'elevator' kernel parameter or rc.local script is the way to solve it.