Spending money? Yep.

No, putting all your eggs into one (hopefully redundant) basket so you only need to yell at one person.

Except that the OS is still provided by a different company to your actual hardware, so there's plenty of room for blame-passing, and most of the OS development is being done on x86 machines by people with no access to IBM Power hardware of any kind.

If I never hear "one throat to choke" again, I'll die a happy man.

This only works well if you can negotiate an acceptable SLA, your main vendor doesn't balk when integrating with subcontractors or other vendors and if you have a rock-solid vendor manager on your side enforcing the SLA.

Needless to say, it often doesn't work that way.

Oh, that works great when you lose power to the rack. Or the datacentre. Or the SAN fails. Or the core routers. Or any of the many other SPOFs that can and do occur in a datacentre.

All of which are accounted for by having two or more of these, combined with the feature they call (I'm not kidding) Geographically Dispersed Parallel Sysplex (GDPS).

You can hook up multiple IBM mainframes remotely and set them up to automatically ensure consistent replication of machine state to various extents depending on your reliability vs. performance tradeoffs and replication distance (latency being the issue), all the way up to active-active operation across systems.

So in other words: It works far better than the failover options most people deploy on their off the shelf servers in their self-wired racks (and yes, I run my own setup across off the shelf servers; and no, they're not nearly as redundant as a pair of IBM mainframes).

Problem is we kitted out two 42U racks in two DCs with HP and EMC kit on VMware and got four humans for five years for less than the comparable quote from IBM. And we've tested replication and failover to the same extent and didnt have to rewrite the 2 million lines or so of code we have...

> All of which are accounted for by having two or more of these, combined with the feature they call (I'm not kidding) Geographically Dispersed Parallel Sysplex (GDPS).

And it is an awesome thing - although I didn't realise it supported zVM these days, rather than just zOS.

In any case, you've still got two baskets, which was my point.

That's why you buy two and put them in different DCs

And that's why IBM has their own bank branch to help customers figure out how to afford that?

Well one of their big customers are the banking sector...

That would be most of their customers I imagine. I work with one who still runs mainframes.