[ovirt-users] iSCSI VLAN host connections - bond or multipath & IPv6

[Ben Bradley]

On 28/09/17 08:32, Yaniv Kaul wrote:
> 
> 
> On Wed, Sep 27, 2017 at 10:59 PM, Ben Bradley <listsbb at virtx.net 
> <mailto:listsbb at virtx.net>> wrote:
> 
>     Hi All
> 
>     I'm looking to add a new host to my oVirt lab installation.
>     I'm going to share out some LVs from a separate box over iSCSI and
>     will hook the new host up to that.
>     I have 2 NICs on the storage host and 2 NICs on the new Ovirt host
>     to dedicate to the iSCSI traffic.
>     I also have 2 separate switches so I'm looking for redundancy here.
>     Both iSCSI host and oVirt host plugged into both switches.
> 
>     If this was non-iSCSI traffic and without oVirt I would create
>     bonded interfaces in active-backup mode and layer the VLANs on top
>     of that.
> 
>     But for iSCSI traffic without oVirt involved I wouldn't bother with
>     a bond and just use multipath.
> 
>      From scanning the oVirt docs it looks like there is an option to
>     have oVirt configure iSCSI multipathing.
> 
> 
> Look for iSCSI bonding - that's the feature you are looking for.

Thanks for the replies.

By iSCSI bonding, do you mean the oVirt feature "iSCSI multipathing" as 
mentioned here 
https://www.ovirt.org/documentation/admin-guide/chap-Storage/ ?

Separate links seems to be the consensus then. Since these are links 
dedicated to iSCSI traffic, not shared. the ovirtmgmt bridge lives on 
top of an active-backup bond on other NICs.

Thanks, Ben

>     So what's the best/most-supported option for oVirt?
>     Manually create active-backup bonds so oVirt just sees a single
>     storage link between host and storage?
>     Or leave them as separate interfaces on each side and use oVirt's
>     multipath/bonding?
> 
>     Also I quite like the idea of using IPv6 for the iSCSI VLAN, purely
>     down to the fact I could use link-local addressing and not have to
>     worry about setting up static IPv4 addresses or DHCP. Is IPv6 iSCSI
>     supported by oVirt?
> 
> 
> No, we do not. There has been some work in the area[1], but I'm not sure 
> it is complete.
> Y.
> 
> [1] 
> https://gerrit.ovirt.org/#/q/status:merged+project:vdsm+branch:master+topic:ipv6-iscsi-target-support
> 
> 
>     Thanks, Ben
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