Resolving Stalled I/O; Additional Information - Novell LINUX ENTERPRISE SERVER 10 SP2 - STORAGE ADMINISTRATION GUIDE 05-15-2009 Administration Manual

To set up queuing I/O for scenarios where all paths fail:
1 In a terminal console, log in as the
2 Open the
/etc/multipath.conf
3 Uncomment the defaults section and its ending bracket, then add the
setting, as follows:
defaults {
default_features "1 queue_if_no_path"
}
4 After you modify the
INITRD on your system, then reboot in order for the changes to take effect.
5 When you are ready to return over to failover for the device I/O, enter:
dmsetup message mapname 0 fail_if_no_path
Replace the mapname with the mapped alias name or the device ID for the device.
This command immediately causes all queued I/O to fail and propagates the error to the calling
application.

5.14 Resolving Stalled I/O

If all paths fail concurrently and I/O is queued and stalled, do the following:
1 Enter the following command at a terminal console prompt:
dmsetup message mapname 0 fail_if_no_path
Replace with the correct device ID or mapped alias name for the device. This causes
mapname
all queued I/O to fail and propagates the error to the calling application.
2 Reactivate queueing by entering the following command at a terminal console prompt:
dmsetup message mapname 0 queue_if_no_path

5.15 Additional Information

For more information about configuring and using multipath I/O on SUSE Linux Enterprise Server,
see the following additional resources in the Novell Support Knowledgebase:
How to Setup/Use Multipathing on SLES (http://support.novell.com/techcenter/sdb/en/2005/
04/sles_multipathing.html)
Troubleshooting SLES Multipathing (MPIO) Problems (Technical Information Document
3231766) (http://www.novell.com/support/
search.do?cmd=displayKC&docType=kc&externalId=3231766&sliceId=SAL_Public)
Dynamically Adding Storage for Use with Multipath I/O (Technical Information Document
3000817) (https://secure-support.novell.com/KanisaPlatform/Publishing/911/
3000817_f.SAL_Public.html)
DM MPIO Device Blacklisting Not Honored in multipath.conf (Technical Information
Document 3029706) (http://www.novell.com/support/
search.do?cmd=displayKC&docType=kc&externalId=3029706&sliceId=SAL_Public&dialogI
D=57872426&stateId=0%200%2057878058)
user.
root
file in a text editor.
/etc/multipath.conf
default_features
file, you must run
mkinitrd
Managing Multipath I/O for Devices
to re-create the
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