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Re: [Xen-API] multipath on 'dual-head' configuration

To: Julian Chesterfield <julian.chesterfield@xxxxxxxxxxxxx>
Subject: Re: [Xen-API] multipath on 'dual-head' configuration
From: George Shuklin <george.shuklin@xxxxxxxxx>
Date: Tue, 17 May 2011 23:36:54 +0400
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Thank you very much for reply!

I done some tests and found it still not working.

here my sr creation (I have done multipath for host already):

xe sr-create type=lvmoiscsi device-config:target=,
name-label=test shared=true

what I'm getting (from pbd-list):

         device-config (MRO): multihomed: true; SCSIid:
1494554000000000031000000000000000000000000000000; targetIQN:
iqn.2011-04.test:test.test; target:,;
    currently-attached ( RO): true
          other-config (MRW):
mpath-1494554000000000031000000000000000000000000000000: [1, 1];
multipathed: true; iscsi_sessions: 1

As you can see multihomelist contain only ONE line.

After pbd-plug I see only one disk (one target, one portal in iscsiadm
-m node) and so on.

I tried to 'cheat' and create pbd with full multihome record:

xe pbd-create sr-uuid=$sr\
host-uuid=b04f46ac-7f99-4964-982b-67738c9e9b36 \
device-config:target=, \
device-config:multihomed=true \
device-config:targetIQN=iqn.2011-04.test:test.test \
device-config:SCSIid=1494554000000000031000000000000000000000000000000 \

but after pbd-plug I still see ONE target.

If I add second target by hand, multipath working as fine as it can, but
I unable to make xapi to do this automatically on pbd-plug.

I tests this on XCP 0.5 and fresh XCP 1.0 installation - same behavior.

Or I don't understand something, or this is a bug.

В Пнд, 16/05/2011 в 17:15 +0100, Julian Chesterfield пишет:
> Hi George,
> You can specify a comma separated list for the iSCSI target in XCP. If 
> both targets advertise the same IQN then you can specify that IQN 
> explicitly as the targetIQN parameter. Alternatively you can select the 
> wildcard entry '*' which will connect to all advertised sessions on 
> every IP address specified in the comma separated list.
> Thanks,
> Julian
> On 16/05/11 17:05, George Shuklin wrote:
> > Good day.
> >
> > Found I unable to setup multipath (XCP 0.5) with two separate hosts
> > connecting to same storage device.
> >
> > Every iscsi target has been sent only it own ip-addresses for target.
> >
> > > From generic linux machine it looks like:
> >
> >,1 iqn.2011-04.test:test.test
> >,1 iqn.2011-04.test:test.test
> >
> > Those IP actually belongs to different machines but allow to access the
> > same block device.
> >
> > In usual linux I simply add iscsi login process to startup, multipath
> > script and it joins paths just by identical serial number and IQN.
> >
> > In XCP I found I need to serve single portal address with all available
> > paths (IPs) to target.
> >
> > Using ISNS is not very good (i do need to build a HA-cluster for that,
> > and it seems be little overkill).
> >
> > That's kinda stuck for me.
> >
> > Here questions:
> >
> > Can I somehow say XCP 'do discovery targets (paths) from two portals for
> > single SR?
> >
> > If I add multipathed device 'by hand' (f.e. by adding iscsi and
> > multipath processing to startup scripts), can I add it to XCP as
> > 'shared' resource (regardless it seems be 'local' for xapi)?
> >
> > Thanks.
> >
> >
> > _______________________________________________
> > xen-api mailing list
> > xen-api@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/mailman/listinfo/xen-api
> >    

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