Bug 442550

Summary: kdump cannot write the dump out to a multipath device
Product: Red Hat Enterprise Linux 5 Reporter: Craig Magina <craig.magina>
Component: kexec-toolsAssignee: Neil Horman <nhorman>
Status: CLOSED CANTFIX QA Contact:
Severity: medium Docs Contact:
Priority: low    
Version: 5.3CC: brsmith, dsulliva, redhat.com
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2008-04-15 15:29:08 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: 550249, 569459    
Attachments:
Description Flags
Experimental patch adding multipath support to mkdumprd none

Description Craig Magina 2008-04-15 14:45:49 UTC 
Description of problem:
The kdump initrd does not contain multipath for a boot from SAN configured
system. This makes it so the crash cannot be written out to the
/dev/mapper/mpath#p# device.

Version-Release number of selected component (if applicable):
RHEL 5.2 snap 4
Kernel 2.6.18-88.el
kexec-tools-1.102pre-16.el5

How reproducible:
Every time.

Steps to Reproduce:
1.Perform a RHEL 5.2-snap4 installation using mpath on the install boot line.
2.Configure kdump to use a multipath device, i.e. /dev/mapper/mpath0p5.
3.Cause a crash via 'echo "c" > /proc/sysrq_trigger'
  
Actual results:
kdump will be unable to write out the dump as the device does not exist.

Expected results:
The dump gets written out to the multipath device.

Additional info:
Tested using Emulex FC HBA connected to an HP EVA 4000.
Comment 1 Neil Horman 2008-04-15 15:29:08 UTC 
Sorry, multipath is something that we're not able to currently do in kdump. 
Getting multipath to work consistently in most situations (especially those
where the path callout is a userspace program), is just to fragile at the
moement.  I've decided that multipath isn't an option for the time being.  I
recommend that you target network based dump target instead (nfs or scp).
Comment 2 Alan Pevec (Fedora) 2010-02-11 23:14:25 UTC 
Created attachment 390413 [details]
Experimental patch adding multipath support to mkdumprd

This might work for some multipath configurations, use at your own risk!
Comment 3 Dave Sullivan 2012-08-03 19:22:12 UTC 
Multipath is not necessary for kdump to work to SAN disk.

See the section "Dumping to a SAN Device"

https://access.redhat.com/knowledge/solutions/6038