[dm-devel] default path for iSCSI

[Michael Menge]

Hi,

first, I hope that I have found the correct list for this question,
as it is not really a devel but a multipath user question.

I want to build a ha-cluster for kvm-virtualisation. I have some blades
and each blade has two network interfaces. The storage for the virtual
machines is provides by two iSCSIs systems which are connected with  
two interfaces each.

My plan was that the iSCSI-traffic should use the second interface by
default, and only use the first interface, if the second path is down,
as the first network interface is used by the other network traffic.

Consulting the manpage and the net i found that setting
path_grouping_policy to group_by_prio and setting the priority
for the default path higher than the other path should do
the trick.

I could set the priority with prio weightedpath, but the
Host part of the HBTL is different on some blades as are the
device names. I would like to use the same multipath config
on all blades and i am certain that both the HBTL and the device name
may change on reboot. Before version 0.4.9 there was the option to
configure prio_callout and use a script to set the priority but that's
not possible any more.

Is there a way to use /dev/disk/by-path in weightedpath?
Is it possible to write my own priority routine and still to use the
multipath package from the distribution? If so is there any  
documentation/examples how to do this?


Regards

Michael Menge




--------------------------------------------------------------------------------

M.Menge                                Tel.: (49) 7071/29-70316
Universität Tübingen                   Fax.: (49) 7071/29-5912
Zentrum für Datenverarbeitung          mail:  
michael.menge at zdv.uni-tuebingen.de
Wächterstraße 76
72074 Tübingen
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