Multipath iSCSI with several IPs
Hello, I want to add an iSCSI based storage domain. For that I add a domain on the Storage tab with one of the IPs (say 10.10.10.1), but for failover purposes I'd like to use multipath to add a failover IP so if the first one fails, LUNs can be reached via the second (say 10.10.10.2). How can this be done in oVirt 4.0.1? I have not seen a way how to add the second IP for multipath purposes. Thank you James
Normally you 1. enter the IP 2. click discover 3. login to whatever was found 4. enter another IP instead of the first 5. goto 2 On Thu, Aug 4, 2016 at 10:13 AM, James Michels < karma.sometimes.hurts@gmail.com> wrote:
Hello,
I want to add an iSCSI based storage domain. For that I add a domain on the Storage tab with one of the IPs (say 10.10.10.1), but for failover purposes I'd like to use multipath to add a failover IP so if the first one fails, LUNs can be reached via the second (say 10.10.10.2).
How can this be done in oVirt 4.0.1? I have not seen a way how to add the second IP for multipath purposes.
Thank you
James
_______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Once upon a time, Dan Yasny <dyasny@gmail.com> said:
Normally you 1. enter the IP 2. click discover 3. login to whatever was found 4. enter another IP instead of the first 5. goto 2
How do you give the oVirt server two IPs (in the same subnet) though? -- Chris Adams <cma@cmadams.net>
Hello Chris, Correct me if I'm wrong but I think Dan meant target's IPs. So if you have a SAN backend with two IP addresses, you first discover LUNs from first IP address, then discover LUNs from the second IP address, and so on... once you have them all, you just check them and click on "OK" so the same target is added with several IP addresses. You don't need to have one IP address per oVirt server. 2016-08-04 16:32 GMT+01:00 Chris Adams <cma@cmadams.net>:
Once upon a time, Dan Yasny <dyasny@gmail.com> said:
Normally you 1. enter the IP 2. click discover 3. login to whatever was found 4. enter another IP instead of the first 5. goto 2
How do you give the oVirt server two IPs (in the same subnet) though?
-- Chris Adams <cma@cmadams.net> _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Once upon a time, James Michels <karma.sometimes.hurts@gmail.com> said:
Correct me if I'm wrong but I think Dan meant target's IPs. So if you have a SAN backend with two IP addresses, you first discover LUNs from first IP address, then discover LUNs from the second IP address, and so on... once you have them all, you just check them and click on "OK" so the same target is added with several IP addresses. You don't need to have one IP address per oVirt server.
Well, to do iSCSI multipath right, you should also have multiple interfaces on each client server, each with its own IP. I'm not sure how you do that with oVirt. -- Chris Adams <cma@cmadams.net>
I guess you mean the 'iSCSI multipath' sub-tab under the 'Datacenters' tab. There you can assign one or more networks to a iSCSI backend. In my opinion you cannot have more than one interface within the same network segment to do multipath, as you would have connectivity issues (not sure if ovirt restricts creating two overlapping networks) 2016-08-04 17:27 GMT+01:00 Chris Adams <cma@cmadams.net>:
Once upon a time, James Michels <karma.sometimes.hurts@gmail.com> said:
Correct me if I'm wrong but I think Dan meant target's IPs. So if you have a SAN backend with two IP addresses, you first discover LUNs from first IP address, then discover LUNs from the second IP address, and so on... once you have them all, you just check them and click on "OK" so the same target is added with several IP addresses. You don't need to have one IP address per oVirt server.
Well, to do iSCSI multipath right, you should also have multiple interfaces on each client server, each with its own IP. I'm not sure how you do that with oVirt.
-- Chris Adams <cma@cmadams.net> _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Once upon a time, James Michels <karma.sometimes.hurts@gmail.com> said:
I guess you mean the 'iSCSI multipath' sub-tab under the 'Datacenters' tab. There you can assign one or more networks to a iSCSI backend. In my opinion you cannot have more than one interface within the same network segment to do multipath, as you would have connectivity issues (not sure if ovirt restricts creating two overlapping networks)
The way I did it on a test 3.6 cluster was to create two networks in oVirt, "storage1" and "storage2". I assigned both networks to the hosts, connected to different NICs, and gave each an IP (in the iSCSI subnet). Then I could set up the iSCSI multipath in the oVirt data center. This seems weird/wrong, and I'm not sure oVirt actually configured both NICs in multipath. -- Chris Adams <cma@cmadams.net>
On Thu, Aug 4, 2016 at 7:27 PM, Chris Adams <cma@cmadams.net> wrote:
Once upon a time, James Michels <karma.sometimes.hurts@gmail.com> said:
Correct me if I'm wrong but I think Dan meant target's IPs. So if you have a SAN backend with two IP addresses, you first discover LUNs from first IP address, then discover LUNs from the second IP address, and so on... once you have them all, you just check them and click on "OK" so the same target is added with several IP addresses. You don't need to have one IP address per oVirt server.
Well, to do iSCSI multipath right, you should also have multiple interfaces on each client server, each with its own IP. I'm not sure how you do that with oVirt.
We support it as well - it's poorly called 'iSCSI bonding'. BTW, having two IPs on a single subnet is not a great idea - it usually mean you have a SPOF somewhere (the switch perhaps?). Y.
-- Chris Adams <cma@cmadams.net> _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Once upon a time, Yaniv Kaul <ykaul@redhat.com> said:
BTW, having two IPs on a single subnet is not a great idea - it usually mean you have a SPOF somewhere (the switch perhaps?).
Two NICs on the server, two NICs on the iSCSI target, each with an IP per NIC, and connected to two switches in between (either stacked or trunked). No SPOF. -- Chris Adams <cma@cmadams.net>
This is a multi-part message in MIME format. ------=_NextPart_000_0014_01D1EE74.FF942150 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Multipath is more a SAN thing, - not a tcp/ip. You should use something like LACP group on two (or more) of your = network interfaces. Also you will have to configure your switch = accordingly. You will not have to worry about second ip. LACP bonded = interface will use one IP, but will fail-over to one of nics if needed. From: James Michels=20 Sent: Thursday, August 4, 2016 5:13 PM To: users=20 Subject: [ovirt-users] Multipath iSCSI with several IPs Hello,=20 I want to add an iSCSI based storage domain. For that I add a domain on = the Storage tab with one of the IPs (say 10.10.10.1), but for failover = purposes I'd like to use multipath to add a failover IP so if the first = one fails, LUNs can be reached via the second (say 10.10.10.2). How can this be done in oVirt 4.0.1? I have not seen a way how to add = the second IP for multipath purposes. Thank you James -------------------------------------------------------------------------= ------- _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users ------=_NextPart_000_0014_01D1EE74.FF942150 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <HTML><HEAD></HEAD> <BODY dir=3Dltr> <DIV dir=3Dltr> <DIV style=3D"FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000"> <DIV> <DIV=20 style=3D'FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: = "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; = DISPLAY: inline'>Multipath=20 is more a SAN thing, - not a tcp/ip.</DIV></DIV> <DIV> <DIV=20 style=3D'FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: = "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; = DISPLAY: inline'>You=20 should use something like LACP group on two (or more) of your network=20 interfaces. Also you will have to configure your switch accordingly. You = will=20 not have to worry about second ip. LACP bonded interface will use one = IP, but=20 will fail-over to one of nics if needed.</DIV></DIV> <DIV> <DIV=20 style=3D'FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: = "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; = DISPLAY: inline'></DIV> <DIV style=3D"FONT: 10pt tahoma"> <DIV style=3D"BACKGROUND: #f5f5f5"> <DIV style=3D"font-color: black"><B>From:</B> <A=20 title=3Dkarma.sometimes.hurts@gmail.com=20 href=3D"mailto:karma.sometimes.hurts@gmail.com">James Michels</A> </DIV> <DIV><B>Sent:</B> Thursday, August 4, 2016 5:13 PM</DIV> <DIV><B>To:</B> <A title=3Dusers@ovirt.org = href=3D"mailto:users@ovirt.org">users</A>=20 </DIV> <DIV><B>Subject:</B> [ovirt-users] Multipath iSCSI with several=20 IPs</DIV></DIV></DIV> <DIV> </DIV></DIV> <DIV=20 style=3D'FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: = "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; = DISPLAY: inline'> <DIV dir=3Dltr>Hello,=20 <DIV> </DIV> <DIV>I want to add an iSCSI based storage domain. For that I add a = domain on the=20 Storage tab with one of the IPs (say 10.10.10.1), but for failover = purposes I'd=20 like to use multipath to add a failover IP so if the first one fails, = LUNs can=20 be reached via the second (say 10.10.10.2).</DIV> <DIV> </DIV> <DIV>How can this be done in oVirt 4.0.1? I have not seen a way how to = add the=20 second IP for multipath purposes.</DIV> <DIV> </DIV> <DIV>Thank you</DIV> <DIV> </DIV> <DIV>James</DIV></DIV> <P> <HR> _______________________________________________<BR>Users mailing=20 list<BR>Users@ovirt.org<BR>http://lists.ovirt.org/mailman/listinfo/users<= BR></DIV></DIV></DIV></BODY></HTML> ------=_NextPart_000_0014_01D1EE74.FF942150--
On Thu, Aug 4, 2016 at 10:24 AM, Tadas <tadas@ring.lt> wrote:
Multipath is more a SAN thing, - not a tcp/ip.
Not when it comes to iSCSI
You should use something like LACP group on two (or more) of your network interfaces.
Absolutely not. It is always better to let multipath deal with paths leading to block storage LUNs, and the underlying fabric does not matter.
Also you will have to configure your switch accordingly. You will not have to worry about second ip. LACP bonded interface will use one IP, but will fail-over to one of nics if needed.
Again, do NOT use bonds for iscsi traffic. Let multipath deal with it.
*From:* James Michels <karma.sometimes.hurts@gmail.com> *Sent:* Thursday, August 4, 2016 5:13 PM *To:* users <users@ovirt.org> *Subject:* [ovirt-users] Multipath iSCSI with several IPs
Hello,
I want to add an iSCSI based storage domain. For that I add a domain on the Storage tab with one of the IPs (say 10.10.10.1), but for failover purposes I'd like to use multipath to add a failover IP so if the first one fails, LUNs can be reached via the second (say 10.10.10.2).
How can this be done in oVirt 4.0.1? I have not seen a way how to add the second IP for multipath purposes.
Thank you
James
------------------------------ _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
_______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
participants (5)
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Chris Adams -
Dan Yasny -
James Michels -
Tadas -
Yaniv Kaul