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by lillecarl 1222 days ago
You just explained how to increase technical debt in as few steps as possible.

The solution is getting a wavelength or dark fiber to the off-site, or throwing out the piece of junk SAN that only works on L2, it's too old by now.
1 comments
skullone 1222 days ago
I didn't say "this solution is easier", simply said someone might find a use case for it. Ya'll are dismissive of something neat with a number of use-cases (I only tossed out just one use case that popped into my head, based on actual experience on a million dollar SAN, that is still supported (and sold!) to this day).
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lillecarl 1222 days ago
If you have a million dollar SAN you have capital to get a real connection where you need it.

The reason I'm very against even discussing this is because people who don't understand the downsides would be open to doing this, shooting themselves in the foot along the way. People who understand the pitfalls just won't and are telling you DON'T, YOUR FOOT WILL HURT.

You could use VXLAN over WireGuard with a lower MTU, attach the VXLAN interfaces to different VRFs and route traffic, it's a somewhat valid usecase.

Switching over the internet is pain, I've got experience. Used to work at an MSP that did this as common procedure, worked fine until it didn't, and noone could explain why. And we're not even talking loops yet, you'll have to build a pretty sick RSTP.

The use-case is at best an SMB migration strategy.

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skullone 1222 days ago
You don't have to explain the perils of extending L2 over any type of WAN to me. There used to be a hard requirement from some SANs to have dark fiber for their replication - not just L2 adjacency (needed actual FC zones extended to another site if I recall). But all is not happy times with L3 links and BGP between things (and even then, BGP configs to achieve anything decent in terms of failover needs BFD or more). But sure, poop all over this fun thought experiment if you want, I doubt anyone's going to deploy this and put a billion dollar company at risk.
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lillecarl 1222 days ago
Yes you need the protocol designed to ensure bidirectional forwarding to keep failover times low. And the routing protocol for exchanging routes.

If the post mentioned the pitfalls it would be a fun experiment. But people don't have to ruin a billion dollar company to do damage, hopefully billion dollar companies can afford staff that knows this is wrong, not every SMB can.

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