[ovirt-users] Best practices for LACP bonds on oVirt

Wed Jul 5 11:05:08 UTC 2017

On Wed, Jul 5, 2017 at 11:54 AM, Vinícius Ferrão <ferrao at if.ufrj.br> wrote:

>
> On 5 Jul 2017, at 05:35, Yaniv Kaul <ykaul at redhat.com> wrote:
>
>
>
> On Wed, Jul 5, 2017 at 7:12 AM, Vinícius Ferrão <ferrao at if.ufrj.br> wrote:
>
>> Adding another question to what Matthias has said.
>>
>> I also noted that oVirt (and RHV) documentation does not mention the
>> supported block size on iSCSI domains.
>>
>> RHV: https://access.redhat.com/documentation/en-us/red_hat_
>> virtualization/4.0/html/administration_guide/chap-storage
>> oVirt: http://www.ovirt.org/documentation/admin-guide/chap-Storage/
>>
>> I’m interested on 4K blocks over iSCSI, but this isn’t really widely
>> supported. The question is: oVirt supports this? Or should we stay with the
>> default 512 bytes of block size?
>>
>
> It does not.
> Y.
>
>
> Discovered this with the hard way, the system is able to detect it as 4K
> LUN, but ovirt-hosted-engine-setup gets confused:
>
>                 [2]     36589cfc00000071cbf2f2ef314a6212c       1600GiB
> FreeNAS iSCSI Disk
>                         status: free, paths: 4 active
>
>                 [3]     36589cfc00000043589992bce09176478
>   200GiB  FreeNAS iSCSI Disk
>                         status: free, paths: 4 active
>
>                 [4]     36589cfc000000992f7abf38c11295bb6
>   400GiB  FreeNAS iSCSI Disk
>                         status: free, paths: 4 active
>
> [2] is 4k
> [3] is 512bytes
> [4] is 1k (just to prove the point)
>
> On the system it’s appears to be OK:
>
> Disk /dev/mapper/36589cfc00000071cbf2f2ef314a6212c: 214.7 GB,
> 214748364800 bytes, 52428800 sectors
> Units = sectors of 1 * 4096 = 4096 bytes
> Sector size (logical/physical): 4096 bytes / 16384 bytes
> I/O size (minimum/optimal): 16384 bytes / 1048576 bytes
>
>
> Disk /dev/mapper/36589cfc00000043589992bce09176478: 214.7 GB,
> 214748364800 bytes, 419430400 sectors
> Units = sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 16384 bytes
> I/O size (minimum/optimal): 16384 bytes / 1048576 bytes
>
> But whatever, just reporting back to the list. It’s a good ideia to have a
> note about it on the documentation.
>

Indeed.
Can you file a bug or send a patch to upstream docs?
Y.

>
> V.
>
>
>
>>
>> Thanks,
>> V.
>>
>> On 4 Jul 2017, at 09:10, Matthias Leopold <matthias.leopold at meduniwien.a
>> c.at> wrote:
>>
>>
>>
>> Am 2017-07-04 um 10:01 schrieb Simone Tiraboschi:
>>
>> On Tue, Jul 4, 2017 at 5:50 AM, Vinícius Ferrão <ferrao at if.ufrj.br <
>> mailto:ferrao at if.ufrj.br <ferrao at if.ufrj.br>>> wrote:
>>    Thanks, Konstantin.
>>    Just to be clear enough: the first deployment would be made on
>>    classic eth interfaces and later after the deployment of Hosted
>>    Engine I can convert the "ovirtmgmt" network to a LACP Bond, right?
>>    Another question: what about iSCSI Multipath on Self Hosted Engine?
>>    I've looked through the net and only found this issue:
>>    https://bugzilla.redhat.com/show_bug.cgi?id=1193961
>>    <https://bugzilla.redhat.com/show_bug.cgi?id=1193961>
>>    Appears to be unsupported as today, but there's an workaround on the
>>    comments. It's safe to deploy this way? Should I use NFS instead?
>> It's probably not the most tested path but once you have an engine you
>> should be able to create an iSCSI bond on your hosts from the engine.
>> Network configuration is persisted across host reboots and so the iSCSI
>> bond configuration.
>> A different story is instead having ovirt-ha-agent connecting multiple
>> IQNs or multiple targets over your SAN. This is currently not supported for
>> the hosted-engine storage domain.
>> See:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1149579
>>
>>
>> Hi Simone,
>>
>> i think my post to this list titled "iSCSI multipathing setup troubles"
>> just recently is about the exact same problem, except i'm not talking about
>> the hosted-engine storage domain. i would like to configure _any_ iSCSI
>> storage domain the way you describe it in https://bugzilla.redhat.com/sh
>> ow_bug.cgi?id=1149579#c1. i would like to do so using the oVirt "iSCSI
>> Multipathing" GUI after everything else is setup. i can't find a way to do
>> this. is this now possible? i think the iSCSI Multipathing documentation
>> could be improved by describing an example IP setup for this.
>>
>> thanks a lot
>> matthias
>>
>>
>>
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>>
>>
>
>
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