Open Stack

Hello Xing and all,

We tried to set up iSCSI multipath with EMC VNX5300.
However, we had some problems with setting the iSCSI multipath with EMC
VNX5300.
So, we analyzed the logs and source codes, and found out that nova-compute
(cinder-volume also same) is using a single iSCSI target(IQN) for login to
multiple (different) portal IP addresses.
VNX5300 has multiple iSCSI ports with different iSCSI target (IQN)s.
(Normally it should use a different iSCSI target(IQN) for each IP address.)

So, we realized that, iSCSI multipath cannot be configured with VNX5300.
But we would like to use iSCSI multipath with EMC VNX5300.

Regards,
Takashi Natsume
NTT Software Innovation Center
Tel: +81-422-59-4399
E-mail: natsume.takashi at lab.ntt.co.jp

From: yang, xing [mailto:xing.yang at emc.com] 
Sent: Friday, November 22, 2013 7:25 AM
To: Carlos Alvarez; openstack at lists.openstack.org
Subject: Re: [Openstack] multipath - EMC vs NetApp

Hi Carlos,

We are working on this issue and will keep you informed.

Thanks,
Xing


From: Carlos Alvarez [mailto:cbalvarez at gmail.com] 
Sent: Monday, November 18, 2013 1:19 PM
To: openstack at lists.openstack.org
Subject: [Openstack] multipath - EMC vs NetApp

Hi All.

I recently added a EMC V-Max storage system, and realized the multipath is
not working. The device is called /dev/mapper/XXXX but when I see the
multipath -ll output, I see just one path. It is working fine with a NetApp
3250. 

Looking into differences, I see the output of the iscsiadm discovery
differs:

Netapp output:
root at grizzly-dev04:~# iscsiadm -m discovery -t sendtargets -p 10.33.5.10
10.33.5.10:3260,1030
iqn.1992-08.com.netapp:sn.0e3c22d9f2ea11e2a2f2123478563412:vs.10
10.33.5.11:3260,1031
iqn.1992-08.com.netapp:sn.0e3c22d9f2ea11e2a2f2123478563412:vs.10

Emc output:
root at grizzly-dev04:~# iscsiadm -m discovery -t sendtargets -p 10.33.5.25
10.33.5.25:3260,1 iqn.1992-04.com.emc:50000973f00bcd44


Looking into the code, the former is clearly what the connect_volume method
is expecting: a single ip which returns both path. I reported it to EMC and
the answer is that it works with netapp because the 3250 has a feature EMC
lacks (called multipath groups). 

Is anybody using multipath with a V-Max?. It should work or EMC is not
supported?

Thanks!
Carlos