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тАО01-18-2011 01:15 PM
тАО01-18-2011 01:15 PM
I have the multipathd service OFF and yet after a server reboots - /dev/dm-NN devices are present and multipath -ll shows multipath devices. "service multipathd status" shows multipathd service is off/stopped
Solved! Go to Solution.
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тАО01-18-2011 01:19 PM
тАО01-18-2011 01:19 PM
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
device-mapper-multipath package includes /etc/udev/rules.d/40-multipath.rules
??
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тАО01-18-2011 01:22 PM
тАО01-18-2011 01:22 PM
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
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тАО01-18-2011 01:32 PM
тАО01-18-2011 01:32 PM
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
is multipath still in your kernel ? lsmod|grep multi
maybe try to pull it out and also rebuild the initrd
or wait for Matti to chime in.. he knows everything ;)
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тАО01-18-2011 01:38 PM
тАО01-18-2011 01:38 PM
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
Environment is RHEL under vMware. We just started using RDMs in physical compatibility mode. So the OS "sees" the already multipathed LUNS (from ESX) and tries to mutipath them too..
I have renamed 40-multipath.rules to _40-multipath.rules and the /dev/dm-NN devices are gone. However, "multipath -ll" still shows multipath definitions.
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тАО01-18-2011 01:43 PM - last edited on тАО05-04-2021 07:36 AM by Ramya_Heera
тАО01-18-2011 01:43 PM - last edited on тАО05-04-2021 07:36 AM by Ramya_Heera
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
what if you deneied them all in the multipath.conf ?
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тАО01-19-2011 08:12 AM
тАО01-19-2011 08:12 AM
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
Tis is a vLinux RHEL server anyway and vSphere manages the multipathing to the SAN LUNs
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тАО01-21-2011 05:08 AM - last edited on тАО05-04-2021 07:37 AM by Ramya_Heera
тАО01-21-2011 05:08 AM - last edited on тАО05-04-2021 07:37 AM by Ramya_Heera
SolutionWhen you install device-mapper-multipath in RHEL 4 and 5, the default multipath.conf file includes an entry that denied everything.
You must remove that entry to enable multipathing - so analogously, adding that denied entry back would disable multipathing.
Device-mapper-multipathing has four main components:
- the userspace "multipath" command
- the userspace "multipathd" daemon
- the kernel module dm_multipath
- the udev rules file for dm-multipath
The multipathd daemon monitors multipath devices for failed paths, switches path groups as necessary, and re-enables failed paths once they become available again - nothing more.
The kernel module and the udev rules do the most of the work when multipathed disks are detected.
So disabling the multipathd daemon/service disables only part of the dm-multipath system... and that isn't the part responsible for detecting new devices.
Because all the userspace components of the dm-multipath system use the /etc/multipath.conf file, denied everything in the configuration file is the correct way to disable dm-multipath.
MK
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тАО01-21-2011 11:19 AM - last edited on тАО05-04-2021 07:36 AM by Ramya_Heera
тАО01-21-2011 11:19 AM - last edited on тАО05-04-2021 07:36 AM by Ramya_Heera
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
Greetings!
And the reboot is a must after the changes to multipath.conf? or is there a way to re-read the multipath.conf after denied or uncommenting the blacklist.
Thanks
Mike.
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тАО01-21-2011 11:58 AM - last edited on тАО05-04-2021 07:35 AM by Ramya_Heera
тАО01-21-2011 11:58 AM - last edited on тАО05-04-2021 07:35 AM by Ramya_Heera
Re: /dev/dm-NN devices and multipaths getting created even if multipathd service is OFF!
No reboot required.
If all your multipathed disks are unmounted (and any databases and other applications that might use raw disks are shut down), you can use "multipath -F" to remove all unused multipath devices (= all of them, if you didn't forget to unmount/shutdown anything).
After that, you can run "multipath -v2": when invoked without the "-l" option, the multipath command will read multipath.conf, and then will re-scan all currently visible disk devices on the system. If all devices are denied in multipath.conf, it should leave all the disks alone. The "-v2" option just gives you immediate visual feedback in case the multipath command still finds an eligible multipathed disk.
MK