Bug 748410

Summary: hrStorageSize from HOST-RESOURCES-TYPES mib reports incorrect size for filesystems > 16TB
Product: Red Hat Enterprise Linux 6 Reporter: Jan Safranek <jsafrane>
Component: net-snmpAssignee: Jan Safranek <jsafrane>
Status: CLOSED ERRATA QA Contact: Dalibor Pospíšil <dapospis>
Severity: medium Docs Contact:
Priority: low    
Version: 6.2CC: ablum, dapospis, famera, jbastian, kajtzu, ksrot, mario.mikocevic, ovasik, rdassen, rvokal, sbradley
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Previously, the snmpd daemon strictly implemented RFC 2780. However, this specification no longer scales well with modern big storage devices with small allocation units, and consequently, snmpd reported a wrong value of the HOST-RESOURCES-MIB::hrStorageSize object when working with a large file system (larger than 16TB), because the accurate value would not fit into Integer32 as specified in the RFC. To address this issue, this update adds a new option to the /etc/snmp/snmpd.conf configuration file, realStorageUnits. By changing the value of this option to 0, users can now enable recalculating all values in hrStorageTable to ensure that the multiplication of hrStorageSize and hrStorageAllocationUnits always produces an accurate device size. On the other hand, the values of hrStorageAllocationUnits are artificial and do not represent the real size of the allocation unit on the storage device.
Story Points: ---
Clone Of: 654384 Environment:
Last Closed: 2012-06-20 07:21:47 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 654384    
Bug Blocks: 741789    

Comment 2 Jan Safranek 2012-02-06 14:23:46 UTC
Note to QA: please test *very* carefully hrStorageTable, hrFSTable and hrDiskTable.

Comment 3 Jan Safranek 2012-02-06 14:23:46 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Previously, the snmpd daemon strictly implemented RFC 2780. However, this specification no longer scales well with modern big storage devices with small allocation units, and consequently, snmpd reported a wrong value of the HOST-RESOURCES-MIB::hrStorageSize object when working with a large file system (larger than 16TB), because the accurate value would not fit into Integer32 as specified in the RFC. To address this issue, this update adds a new option to the /etc/snmp/snmpd.conf configuration file, realStorageUnits. By changing the value of this option to 0, users can now enable recalculating all values in hrStorageTable to ensure that the multiplication of hrStorageSize and hrStorageAllocationUnits always produces an accurate device size. On the other hand, the values of hrStorageAllocationUnits are artificial and do not represent the real size of the allocation unit on the storage device.

Comment 8 errata-xmlrpc 2012-06-20 07:21:47 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.

http://rhn.redhat.com/errata/RHSA-2012-0876.html