Bug 1092308

Summary:	backport diskio device filtering
Product:	Red Hat Enterprise Linux 7	Reporter:	Karel Srot <ksrot>
Component:	net-snmp	Assignee:	Jan Safranek <jsafrane>
Status:	CLOSED ERRATA	QA Contact:	Dalibor Pospíšil <dapospis>
Severity:	medium	Docs Contact:
Priority:	high
Version:	7.0	CC:	dapospis
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	net-snmp-5.7.2-24.el7	Doc Type:	Bug Fix
Doc Text:	The snmpd service parses the /proc/diskstats file to track disk usage statistics for UCD-DISKIO-MIB::diskIOTable. On systems with a large number of block devices, /proc/diskstats may be large in size and parsing it can take a non-trivial amount of CPU time. With this update, Net-SNMP introduces a new option, 'diskio', in the etc/snmp/snmpd.conf file, which can be used to explicitly specify devices that should be monitored. Only these whitelisted devices are then reported in UCD-DISKIO-MIB::diskIOTable, thus speeding up snmpd on systems with numerous block devices.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2015-11-19 11:45:37 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:
Embargoed:

Description Karel Srot 2014-04-29 06:01:27 UTC

Description of problem:

diskio device filtering has been already implemented in RHEL-6 as bug 990674,
upstream git commit 5be210c90870ff6bab193d497d401b92c1d50db9.

the Net-SNMP daemon, parses /proc/diskstats to track disk usage statistics for UCD-DISKIO-MIB::diskIOTable. On machines with large number of block devices, this /proc/diskstats is large and its parsing can take non-trivial amount of CPU. With this update, Net-SNMP introduces new option 'diskio' in /etc/snmp/snmpd.conf, which can be used to specify devices, which should be monitored. Only these whitelisted devices are then reported in UCD-DISKIO-MIB::diskIOTable, thus speeding up snmpd on systems with lot of block devices.

Please backport also to RHEL-7 so we don't regress.

Comment 7 errata-xmlrpc 2015-11-19 11:45:37 UTC

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.

https://rhn.redhat.com/errata/RHSA-2015-2345.html