Network traffic type assignment

[Fred Blum]

Hi all,

I am struggling with the traffic assignment to subnets. I read that even when you try to seperate Management from Replication traffic that still Replication Control traffic will go over the Management subnet. So it does not  seem to be possible to really seperate Management and Replication Traffic.

Furthermore it is recommended NOT to use the iscsi subnet for replication. 

I am missing a matrix of the possible Traffic Types and Traffic assignment combinations / best practises..

I want to assign to the ISCSI network the traffic Type Data Only with Traffic Assignment ISCSI  Only. So no management, group or replication traffic. This seems straight forward. 

Now the Management network. I want to set Management with multiarray intragroup replication traffic.

When I set Traffic Assignment Management Only I am not forced to set a data discovery IP adress.. Will intragroup and replication traffic still work?

When I select Traffic Type Group Only and Management + Data I am forced to set a data discovery IP adress plus data IP Adresses on both NICS. I do not understand why you need to set a data discovery IP adress when you are not using ISCSI.

The Array Controllers already have a Management Group IP adress and diagnostic IP adresses in the management VLAN. The GUI accepts it when you use the Management Group IP adress for the Data Discovery adress. I do not think this is right in a multi-array group. You can also assign the Diagnostics IP adresses to the nics without a warning. Only when clicking the Diagnostics tab you will see a warning that it is misconfigured.

So for the multiarray group replication data in the management subnet (no iscsi) you also need to set a data discovery IP adress and Data IP adresses on the nics?

Regards,

Fred

[Nick_Dyer]

Fred,

Might be worth getting in touch with your local SE or Nimble Support as a sounding board, as it's always better to have questions answered in real time rather than on a forum. However, i'll give it a shot.

For asynchronous replication we can use any subnet for replication data traffic - management, iSCSI data (although it would mean routing iSCSI which isn't a great idea) or even a dedicated vLAN or subnet for replication. In NimbleOS 5.1 and below, whilst data can traverse any subnet - the management 'control' of the replication partnership & traffic still requires the management network. You'll be pleased to hear in NimbleOS 5.2 this isn't the case, and now the control and management of traffic also takes place over the subnet you define for data.  I'll have a blog live next week on some of the new enhancements with NimbleOS 5.2 which you'll be able to consume.

For synchronous replication we consume replication by using the scale-out group functionality of the array and uses a "group" data type within the array platform to transfer data from array to array. "Group" data can reside on the management network, but could also reside on the iSCSI subnet - or some other subnet that you choose by setting the "group only" flag in the networking of the array.

Hope this helps?

[Fred Blum · Accepted solution]

Hi Nick,

Thanks for the information. I also found this information to be helpful regarding setting it up in the 5.1:

https://community.hpe.com/t5/hpe-storage-tech-insiders/setting-up-replication-over-a-dedicated-interface/ba-p/6986487#.XtuIOzozZEZ 

And Support send me this white paper which makes it more clear:

https://infosight.hpe.com/InfoSight/media/cms/active/public/HPE_Nimble_Storage_Peer_Persistence_Deployment_Considerations.pdf