Re: [Users] iSCSI multipath with EqualLogic SAN

22 Feb 2013

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Never heard of HIT before.
Seems to be a proprietary Dell solution?
Ok, I just high-lighted the classical /most common SAN connection :)

We are using a Dell MD3220i (much smaller then EQ series) with MD1200 units=
, and yes the network configuration for subnet separated multipathing seems=
 to be more complicated at first,
but it will give you load-balancing and auto fail-over functionality.

Of course a nice and quick alternative as suggested here "...but you can co=
nfigure your nodes to use the other paths using the command line on the Cen=
tos nodes...",
is also possible.

Cheers,
Sven.

Von: Chris Noffsinger [mailto:cnoffsin@gmail.com]
Gesendet: Donnerstag, 21. Februar 2013 20:05
An: Jonathan Horne
Cc: Sven Knohsalla; Baptiste AGASSE; users@ovirt.org
Betreff: Re: [Users] iSCSI multipath with EqualLogic SAN

We have 2 Equallogic PS4100s.  And someone more knowledgeable may prove me =
wrong here but,

Multipathd is not my most favorite thing to configure, but you can configur=
e your nodes to use the other paths using the command line on the Centos no=
des.

Yeah Dell will tell you that they want you to use their software (like the =
mem plugin in Vmware) but the Linux OS will see the other paths and treat i=
t like any other SAN, you are just going to have to configure them to use t=
hem.   The link sent earlier in the thread is the official guide to doing t=
hat.

https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/p=
df/DM_Multipath/Red_Hat_Enterprise_Linux-6-DM_Multipath-en-US.pdf

Here is another Doc I used that is for Rhel5 but I beleive the multipath co=
mmands are the same:

http://www.equallogic.com/WorkArea/downloadasset.aspx?id=3D8727

On Thu, Feb 21, 2013 at 1:09 PM, Jonathan Horne <jhorne@skopos.us<mailto:jh=
orne@skopos.us>> wrote:
Ive discussed this at length with dell's EQ support team, and on a regular =
system that's connected in to an equallogic san, all the iscsi ports would =
be on the same subnet. The kicker is, dell really wants you to use their s=
pecialized driver/iscsiinitiator to access (known as their HIT kit...host i=
ntegration tools), and the HIT kit handles establishing all the multiple se=
ssions into the EQ SAN.

Unfortunately, equallogic  doesnt support RHEV (and thus ovirt), and ovirt =
does not seem to execute the commands the HIT driver would want to intitiat=
e multiple connections.

Dell says that the use of bonding for iscsi just begs for tcp retransmits. =
 since bonding is the only method of failover I see for now, were using any=
way against their recommendations (so far zero retransmits, but were not ru=
nning our systems hard yet).

Cheers,
Jonathan

-----Original Message-----
From: users-bounces@ovirt.org<mailto:users-bounces@ovirt.org> [mailto:users=
-bounces@ovirt.org<mailto:users-bounces@ovirt.org>] On Behalf Of Sven Knohs=
alla
Sent: Thursday, February 21, 2013 8:55 AM
To: Baptiste AGASSE
Cc: users@ovirt.org<mailto:users@ovirt.org>
Subject: Re: [Users] iSCSI multipath with EqualLogic SAN

Hi Baptiste,

usually a SAN doesn't support bonding (see post of Nicolas) of its interfac=
es, so you have to use multipathing technology.

You have to separate all nics in different subnets so multipath can work.
Command multipath -ll with show the connected paths.

If you "merge" all paths in one subnet you will have the result/behavior yo=
u just posted.

So this is less oVirt related, more network specific.
We have a running iSCSI config with 4 networks and oVirt runs well.

Maybe the following link will help you here:
https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/p=
df/DM_Multipath/Red_Hat_Enterprise_Linux-6-DM_Multipath-en-US.pdf

Cheers,
Sven.

-----Urspr=FCngliche Nachricht-----
Von: users-bounces@ovirt.org<mailto:users-bounces@ovirt.org> [mailto:users-=
bounces@ovirt.org<mailto:users-bounces@ovirt.org>] Im Auftrag von Nicolas E=
carnot
Gesendet: Donnerstag, 21. Februar 2013 15:48
An: users@ovirt.org<mailto:users@ovirt.org>
Betreff: Re: [Users] iSCSI multipath with EqualLogic SAN

Le 21/02/2013 11:30, Baptiste AGASSE a =E9crit :
...
Hi all,
I'm testing ovirt 3.1 on centos boxes. I setup ovirt management node
and 4 vdsm hosts. vdsm hosts have 2 nics on the SAN subnet. When i
create a iscsi storage domain, it use only one of the two nics on the
SAN network (showed with iscsiadm -m session on vdsm nodes). Does
ovirt support multiples nics on the same subnet for iscsi SAN
connection ?
...
Of course a nice and quick alternative as suggested here “…but=
 you can configure your nodes to use the other paths using the command line=
 on the Centos nodes…”,<o:p></o:p>is also possible.<o:p></o:p><span=
...
<o:p> </o:p></div>Multipathd is not my most =
favorite thing to configure, but you can configure your nodes to use the ot=
her paths using the command line on the Centos nodes.<o:p></o:p><div><p=
 class=3DMsoNormal><o:p> </o:p></div><div>Yea=
h Dell will tell you that they want you to use their software (like the mem=
...
 Subject: Re: [Users] iSCSI multipath with EqualLogic SAN Hi Bap=
tiste, usually a SAN doesn't support bonding (see post of Nicolas) o=
f its interfaces, so you have to use multipathing technology. You ha=
ve to separate all nics in different subnets so multipath can work. Comm=
and multipath -ll with show the connected paths. If you "merge&=
quot; all paths in one subnet you will have the result/behavior you just po=
sted. So this is less oVirt related, more network specific. We ha=
ve a running iSCSI config with 4 networks and oVirt runs well. Maybe=
I don't know if this is the best setup, but this is exaclty what I did (iSC=
SI with an Equllogic SAN) : I bonded 4 interfaces of the iSCSI subnet, and =
it's working fine so far...

--
Nicolas Ecarnot
_______________________________________________
Users mailing list
Users@ovirt.org<mailto:Users@ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users
_______________________________________________
Users mailing list
Users@ovirt.org<mailto:Users@ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users

________________________________
This is a PRIVATE message. If you are not the intended recipient, please de=
lete without copying and kindly advise us by e-mail of the mistake in deliv=
ery. NOTE: Regardless of content, this e-mail shall not operate to bind SKO=
POS to any order or other contract unless pursuant to explicit written agre=
ement or government initiative expressly permitting the use of e-mail for s=
uch purpose.
_______________________________________________
Users mailing list
Users@ovirt.org<mailto:Users@ovirt.org>
http://lists.ovirt.org/mailman/listinfo/users

--
Chris Noffsinger

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</o:shapelayout></xml><![endif]--></head><body lang=3DEN-US link=3Dblue vli=
nk=3Dpurple><div class=3DWordSection1><p class=3DMsoNormal><span style=3D'f=
ont-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Never hea=
rd of HIT before.<br>Seems to be a proprietary Dell solution?<br>Ok, I just=
 high-lighted the classical /most common SAN connection :)<br><br>We are us=
ing a Dell MD3220i (much smaller then EQ series) with MD1200 units, and yes=
 the network configuration for subnet separated multipathing seems to be mo=
re complicated at first,<o:p></o:p></span></p><p class=3DMsoNormal><span st=
yle=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>b=
ut it will give you load-balancing and auto fail-over functionality.<br><br=
 style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D=
'><o:p> </o:p></span></p><p class=3DMsoNormal><span style=3D'font-size=
:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Cheers,<br>Sven.<=
o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:11.0pt;f=
ont-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></=
p><p class=3DMsoNormal><b><span style=3D'font-size:10.0pt;font-family:"Taho=
ma","sans-serif"'>Von:</span></b><span style=3D'font-size:10.0pt;font-famil=
y:"Tahoma","sans-serif"'> Chris Noffsinger [mailto:cnoffsin@gmail.com] <br>=
<b>Gesendet:</b> Do</span><span lang=3DDE style=3D'font-size:10.0pt;font-fa=
mily:"Tahoma","sans-serif"'>nnerstag, 21. Februar 2013 20:05<br><b>An:</b> =
Jonathan Horne<br><b>Cc:</b> Sven Knohsalla; Baptiste AGASSE; users@ovirt.o=
rg<br><b>Betreff:</b> Re: [Users] iSCSI multipath with EqualLogic SAN<o:p><=
/o:p></span></p><p class=3DMsoNormal><o:p> </o:p></p><div><p class=3DM=
soNormal>We have 2 Equallogic PS4100s.  And someone more knowledgeable=
 may prove me wrong here but,<o:p></o:p></p></div><div><p class=3DMsoNormal=
 plugin in Vmware) but the Linux OS will see the other paths and treat it l=
ike any other SAN, you are just going to have to configure them to use them=
.   The link sent earlier in the thread is the official guide to doing=
 that.<o:p></o:p></p></div><div><p class=3DMsoNormal><o:p> </o:p></p><=
/div><div><p class=3DMsoNormal><a href=3D"https://access.redhat.com/knowled=
ge/docs/en-US/Red_Hat_Enterprise_Linux/6/pdf/DM_Multipath/Red_Hat_Enterpris=
e_Linux-6-DM_Multipath-en-US.pdf" target=3D"_blank">https://access.redhat.c=
om/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/pdf/DM_Multipath/Red_Hat=
_Enterprise_Linux-6-DM_Multipath-en-US.pdf</a><br><br><br>Here is another D=
oc I used that is for Rhel5 but I beleive the multipath commands are the sa=
me:<o:p></o:p></p></div><div><p class=3DMsoNormal><o:p> </o:p></p></di=
v><div><p class=3DMsoNormal><a href=3D"http://www.equallogic.com/WorkArea/d=
ownloadasset.aspx?id=3D8727">http://www.equallogic.com/WorkArea/downloadass=
et.aspx?id=3D8727</a><o:p></o:p></p></div><div><p class=3DMsoNormal><o:p>&n=
bsp;</o:p></p></div><div><p class=3DMsoNormal><o:p> </o:p></p><div><p =
class=3DMsoNormal>On Thu, Feb 21, 2013 at 1:09 PM, Jonathan Horne <<a hr=
ef=3D"mailto:jhorne@skopos.us" target=3D"_blank">jhorne@skopos.us</a>> w=
rote:<o:p></o:p></p><p class=3DMsoNormal>Ive discussed this at length with =
dell's EQ support team, and on a regular system that's connected in to an e=
quallogic san, all the iscsi ports would be on the same subnet.  The k=
icker is, dell really wants you to use their specialized driver/iscsiinitia=
tor to access (known as their HIT kit...host integration tools), and the HI=
T kit handles establishing all the multiple sessions into the EQ SAN.<br><b=
r>Unfortunately, equallogic  doesnt support RHEV (and thus ovirt), and=
 ovirt does not seem to execute the commands the HIT driver would want to i=
ntitiate multiple connections.<br><br>Dell says that the use of bonding for=
 iscsi just begs for tcp retransmits.  since bonding is the only metho=
d of failover I see for now, were using anyway against their recommendation=
s (so far zero retransmits, but were not running our systems hard yet).<br>=
<br>Cheers,<br>Jonathan<br><br>-----Original Message-----<br>From: <a href=
=3D"mailto:users-bounces@ovirt.org">users-bounces@ovirt.org</a> [mailto:<a =
href=3D"mailto:users-bounces@ovirt.org">users-bounces@ovirt.org</a>] On Beh=
alf Of Sven Knohsalla<br>Sent: Thursday, February 21, 2013 8:55 AM<br>To: B=
aptiste AGASSE<br>Cc: <a href=3D"mailto:users@ovirt.org">users@ovirt.org</a=
 the following link will help you here:<br><a href=3D"https://access.redhat=
.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/pdf/DM_Multipath/Red_H=
at_Enterprise_Linux-6-DM_Multipath-en-US.pdf" target=3D"_blank">https://acc=
ess.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/pdf/DM_Multi=
path/Red_Hat_Enterprise_Linux-6-DM_Multipath-en-US.pdf</a><br><br>Cheers,<b=
r>Sven.<br><br>-----Urspr=FCngliche Nachricht-----<br>Von: <a href=3D"mailt=
o:users-bounces@ovirt.org">users-bounces@ovirt.org</a> [mailto:<a href=3D"m=
ailto:users-bounces@ovirt.org">users-bounces@ovirt.org</a>] Im Auftrag von =
Nicolas Ecarnot<br>Gesendet: Donnerstag, 21. Februar 2013 15:48<br>An: <a h=
ref=3D"mailto:users@ovirt.org">users@ovirt.org</a><br>Betreff: Re: [Users] =
iSCSI multipath with EqualLogic SAN<br><br>Le 21/02/2013 11:30, Baptiste AG=
ASSE a =E9crit :<br>> Hi all,<br>><br>> I'm testing ovirt 3.1 on c=
entos boxes. I setup ovirt management node<br>> and 4 vdsm hosts. vdsm h=
osts have 2 nics on the SAN subnet. When i<br>> create a iscsi storage d=
omain, it use only one of the two nics on the<br>> SAN network (showed w=
ith iscsiadm -m session on vdsm nodes). Does<br>> ovirt support multiple=
s nics on the same subnet for iscsi SAN<br>> connection ?<br><br>I don't=
 know if this is the best setup, but this is exaclty what I did (iSCSI with=
 an Equllogic SAN) : I bonded 4 interfaces of the iSCSI subnet, and it's wo=
rking fine so far...<br><br>--<br>Nicolas Ecarnot<br>______________________=
_________________________<br>Users mailing list<br><a href=3D"mailto:Users@=
ovirt.org">Users@ovirt.org</a><br><a href=3D"http://lists.ovirt.org/mailman=
/listinfo/users" target=3D"_blank">http://lists.ovirt.org/mailman/listinfo/=
users</a><br>_______________________________________________<br>Users maili=
ng list<br><a href=3D"mailto:Users@ovirt.org">Users@ovirt.org</a><br><a hre=
f=3D"http://lists.ovirt.org/mailman/listinfo/users" target=3D"_blank">http:=
//lists.ovirt.org/mailman/listinfo/users</a><br><br>_______________________=
_________<br>This is a PRIVATE message. If you are not the intended recipie=
nt, please delete without copying and kindly advise us by e-mail of the mis=
take in delivery. NOTE: Regardless of content, this e-mail shall not operat=
e to bind SKOPOS to any order or other contract unless pursuant to explicit=
 written agreement or government initiative expressly permitting the use of=
 e-mail for such purpose.<br>______________________________________________=
_<br>Users mailing list<br><a href=3D"mailto:Users@ovirt.org">Users@ovirt.o=
rg</a><br><a href=3D"http://lists.ovirt.org/mailman/listinfo/users" target=
=3D"_blank">http://lists.ovirt.org/mailman/listinfo/users</a><o:p></o:p></p=
...
</div><p class=3DMsoNormal><br><br clear=3Dall><o:p></o:p></p><div><p clas=
s=3DMsoNormal><o:p> </o:p></p></div><p class=3DMsoNormal>-- <br>Chris =
Noffsinger<o:p></o:p></p></div></div></body></html>=
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