Separate physical network for backup?

Thanks Ian. Those are our thoughts too but we're meeting resistance from other groups in our department, hence the quest to find some concrete evidence that we're "behind the times" in the way we do things now.

I'm not a customer so probably can't give you the data points you're looking for but my understanding of the history of dedicated backup networks is that they were largely created to deal with the impact of trying to send the huge amounts of data generated by backup products of the time across the production network. With modern backup technologies (especially de-dupe), that's no longer a major concern since only a tiny fraction of the data traverses the network on a daily basis.

I think if you look at the reasons that a separate physical network was established in your environment, you may be able to attack the question from that angle as well. Having a single physical network dramatically simplifies network management so if the original reasons for establishing a dedicated backup network no longer exist, it's probably time to re-think the approach.

In our environment, we have never used split networks for production and backup traffic.  The sheer overhead of additional network connectivity provides very little benefit.  In our case, we've had servers with single network NICs and servers with dual, redundant NICs.  Adding yet-another NIC, just for backup traffic, would only serve to add more confusion and physical congestion.

In other environments I've been engaged in, we used dual physical NIC in redundant configurations, but used VLAN tagging to logically isolate backup traffic and production traffic.  This required significantly less network cabling, and it still provided a bit of performance improvement, as our Cisco switches let us mix MTU sizes and leverage Netflow and other features for performance benefit.

Let us know if that helps!

Karl

Thanks Karl. May I ask what industry sector(s) your "other environments" were in?

Sure -

I was a professional services engineer for EMC for a time.  I worked on a few customer environments (auto, healthcare insurance and pharma) helping them migrate storage environments, standup greenfield environments and so on.

Two customers were building out net-new data centers.  In both cases, we helped them scope and scale the data center network to reduce cabling requirements but still fit a need for a highly-available network that the Network team could perform code upgrades and collect data with Netflow.

Let me know if that helps!

Karl

I have recently set up a separate "backup network" for an Oracle Exadata system backing up to IDPA, but the result should be the same if you are using Avamar with Data Domain. There should be free Ethernet ports on Data Domain to configure a separate ifgroup and there are a few tweaks on clients that need to be done. If you're looking for a solution that does not require setting up a large install base of backup clients, I may be able to help out. Reach out to if interested.