9:37 a.m.
Hi Dan,
The way you describe it I should have 2 storage backends with 2 IPs for the
same SAN backend, right? The problem I see is that when you create a disk
for a VM, you assign it to only one storage domain... so if the first
fails, how will oVirt know which one should use as failover?
Thank you
2016-08-04 15:20 GMT+01:00 Dan Yasny <dyasny(a)gmail.com>:
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(a)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(a)ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
>
9:39 a.m.
New subject: Fwd: Multipath iSCSI with several IPs
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On 04/08/16 15:37, James Michels wrote:
Hi Dan,
The way you describe it I should have 2 storage backends with 2 IPs
for the same SAN backend, right? The problem I see is that when you
create a disk for a VM, you assign it to only one storage domain... so
if the first fails, how will oVirt know which one should use as failover?
No, multipath is the *same* storage (ie LUN) exposed via two different
network paths.
Alex
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<p>On 04/08/16 15:37, James Michels wrote:<br>
</p>
<blockquote
cite="mid:CALws9xWUKP9_UBqVYjiyPbNUBn1SBdVwJn7H-SJR-1_FXZ2rFQ@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_quote">
<div dir="ltr">Hi Dan,
<div><br>
</div>
<div>The way you describe it I should have 2 storage
backends with 2 IPs for the same SAN backend, right? The
problem I see is that when you create a disk for a VM, you
assign it to only one storage domain... so if the first
fails, how will oVirt know which one should use as
failover?</div>
<div><br>
</div>
<br>
</div>
</div>
</div>
</blockquote>
No, multipath is the *same* storage (ie LUN) exposed via two
different network paths.<br>
<br>
Alex<br>
<br><pre>
--
This message is intended only for the addressee and may contain
confidential information. Unless you are that person, you may not
disclose its contents or use it in any way and are requested to delete
the message along with any attachments and notify us immediately.
This email is not intended to, nor should it be taken to, constitute advice.
The information provided is correct to our knowledge & belief and must not
be used as a substitute for obtaining tax, regulatory, investment, legal or
any other appropriate advice.
"Transact" is operated by Integrated Financial Arrangements Ltd.
29 Clement's Lane, London EC4N 7AE. Tel: (020) 7608 4900 Fax: (020) 7608 5300.
(Registered office: as above; Registered in England and Wales under
number: 3727592). Authorised and regulated by the Financial Conduct
Authority (entered on the Financial Services Register; no. 190856).
</pre><br>
</body>
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9:42 a.m.
New subject: Fwd: Multipath iSCSI with several IPs
On Thu, Aug 4, 2016 at 10:37 AM, James Michels <
karma.sometimes.hurts(a)gmail.com> wrote:
Hi Dan,
The way you describe it I should have 2 storage backends with 2 IPs for
the same SAN backend, right?
Every iSCSI SAN has multiple portals (usually one on each storage
controller, and each with it's own IP), and when you create a target you
assign it the portals through which it should be accessible. So if you have
two portals (two IPs) assigned to a target (LUN), you can access it via two
paths, each path leading through a different portal/IP to the same
target/LUN.
What do you use for your iSCSI backend?
The problem I see is that when you create a disk for a VM, you assign
it
to only one storage domain... so if the first fails, how will oVirt know
which one should use as failover?
There is only one disk, but it sits on a target, which can be accessed via
two different IPs. oVirt stores all the iSCSI portal IPs you give it as
described in my first response in a database, and connects to them when
connecting to the storage domain. If one is down, multipath will mark the
path as down and keep using other IPs to access the same LUN
Thank you
2016-08-04 15:20 GMT+01:00 Dan Yasny <dyasny(a)gmail.com>:
> 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(a)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(a)ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>
_______________________________________________
Users mailing list
Users(a)ovirt.org
http://lists.ovirt.org/mailman/listinfo/users
10:04 a.m.
New subject: Fwd: Multipath iSCSI with several IPs
Nice, now it's crystal clear. This is an Huawei Oceanstor disk array which
we want to test with ovirt so we can see performance, how ovirt behaves
with situations where one controller is disconnected etc., that's why we
wanted to implement multipath.
Thanks for the insight!
James
2016-08-04 15:42 GMT+01:00 Dan Yasny <dyasny(a)gmail.com>:
On Thu, Aug 4, 2016 at 10:37 AM, James Michels <
karma.sometimes.hurts(a)gmail.com> wrote:
> Hi Dan,
>
> The way you describe it I should have 2 storage backends with 2 IPs for
> the same SAN backend, right?
>
Every iSCSI SAN has multiple portals (usually one on each storage
controller, and each with it's own IP), and when you create a target you
assign it the portals through which it should be accessible. So if you have
two portals (two IPs) assigned to a target (LUN), you can access it via two
paths, each path leading through a different portal/IP to the same
target/LUN.
What do you use for your iSCSI backend?
> The problem I see is that when you create a disk for a VM, you assign it
> to only one storage domain... so if the first fails, how will oVirt know
> which one should use as failover?
>
>
There is only one disk, but it sits on a target, which can be accessed via
two different IPs. oVirt stores all the iSCSI portal IPs you give it as
described in my first response in a database, and connects to them when
connecting to the storage domain. If one is down, multipath will mark the
path as down and keep using other IPs to access the same LUN
> Thank you
>
> 2016-08-04 15:20 GMT+01:00 Dan Yasny <dyasny(a)gmail.com>:
>
>> 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(a)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(a)ovirt.org
>>> http://lists.ovirt.org/mailman/listinfo/users
>>>
>>>
>>
>
>
> _______________________________________________
> Users mailing list
> Users(a)ovirt.org
> http://lists.ovirt.org/mailman/listinfo/users
>
>
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3 comments
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participants (3)
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Alex Crow -
Dan Yasny -
James Michels