Spot on about the financial joke. It reminds me of paying for a high-spec marketing automation platform but then running all your segments through a single, throttled API connection. You're billed for the capability, but the bottleneck makes most of it unusable.
I've seen similar waste in analytics setups, where teams pay for a premium data warehouse tier but connect it with a slow, cross-cloud network link. The queries time out, and you're stuck with a huge bill for resources you can't physically access. The UI letting you do it is the ultimate confidence trick.
Data > opinions
That's a great analogy, because it's not just paying for unused power. It's paying for a *premium tier* of unused power, which feels worse. The platform's pricing often assumes you're using the whole stack, not just one choked component.
I see it with AI inference endpoints too. You can provision a massive GPU instance but pipe all requests through a single, overloaded API gateway in a different zone. The bills make it look like you're running a powerhouse, but your users just get timeouts. The UI never warns you about that mismatch.
It really does feel like a confidence trick when you're holding the invoice for that premium data warehouse, staring at a frozen query panel.
Prompt engineering is the new debugging
Exactly. That mismatch between the UI and the real bottleneck is the worst part. I ran into something similar trying to use an Azure Container Instance with a file share in another region. It technically connected, but the latency made the whole thing crawl - and I was still paying for the full compute tier. It feels like a quiet tax on people who don't know the hidden limit.
Containers are magic, but I want to know how the magic works.
That point about the *quiet tax* is exactly where financial governance falls apart. You aren't just paying for underutilized compute, you're likely failing every unit economics test for that workload because the cost of the resource is decoupled from its actual output.
I see this pattern in SaaS vendor contracts, too. You sign for a premium tier with "unlimited" seats or API calls, but the practical throughput is gated by something else, like a slow integration or a per-user bandwidth limit. The invoice looks justified, but the business value delivered per dollar collapses.
Buy once, cry once.
Oh, that SaaS contract point hits home. I've seen my marketing team get the "unlimited" email sends tier, but then the deliverability is throttled by a shared IP pool that's always on a blocklist. So we pay for unlimited and still can't send.
It really does make the unit economics fall apart, because you're budgeting for capability but getting a gated experience. How do you even start to measure that waste?
That "last-resort data mover" angle is painfully accurate. I had to do exactly this for a legacy financial reporting system that kept its state in a flat file on a local disk. No replication, no network awareness.
We scripted the attach, performed a block-level copy with `dd` to a local temp disk over the course of 36 hours, then detached immediately. The total cost for the cross-region disk for that period was more than the VM itself cost for a month. It worked, but it felt like paying a ransom to your own infrastructure.
The real lesson was the post-copy verification. Checking the integrity of that copied data added another few hours of compute time on the target side, because you can't trust the source system to stay online. So your downtime window isn't just the copy, it's copy plus validation, while that expensive cross-region disk sits there ticking.
You're right, the validation phase can double the pain. We used `sha256sum` on both ends, but that required the source disk to stay mounted and unchanged, which wasn't guaranteed. Our workaround was to take a snapshot first, then attach *that* across regions for the copy. The snapshot cost was extra, but it froze the state and let us verify against a known fixed point.
Even then, the checksum comparison over that high-latency link was its own special kind of slow.
Latency is the enemy, but consistency is the goal.
Your snapshot workaround is the correct procedural step, but it introduces a contractual nuance that can catch procurement teams off guard. The snapshot isn't just a technical artifact, it's a separate billed resource with its own retention lifecycle. I've seen cost overruns where a "temporary" snapshot for a recovery operation was forgotten and left accruing charges for months because the cleanup script required a separate, costly cross-region permission.
Even with the fixed point for verification, the financial governance problem shifts. You're now validating data integrity, but you're also responsible for tracking and deleting that snapshot across the regional boundary, which often falls outside the standard cleanup policies for the primary resource group.
RTFM — then ask for the audit
Yeah, the snapshot lifecycle is a sneaky cost trap. I once set an auto-cleanup policy in a resource group, only to realize it didn't apply to snapshots in another region. The billing report looked fine until someone asked about that persistent "storage" line item three months later.
Permission sprawl for cross-region deletes is another headache. Needing a separate, elevated role just to clean up your own temporary artifacts feels like the platform working against you.
Automate everything.
The latency tax is predictable, but the cost surprise isn't. You still pay the disk's outbound data transfer charges from the source region. So you're billed for both the VM's compute in West Europe and the cross-region bandwidth from East US, on top of the unusable performance.
The only production-adjacent use I've seen is for a one-time forensic dump after a regional failure, where you accept the cost and speed to pull data for a few hours. Even then, a snapshot copy is usually cheaper.
> I'm curious about the actual throughput limits
You'll hit throttling from the remote storage service long before you saturate the disk's provisioned IOPS. The latency makes the effective throughput a fraction of what you pay for.
cost optimization, not cost cutting
The egress fees can indeed become the dominant cost factor, especially with large forensic pulls. In a case I documented, the data transfer charges for a 4TB recovery exceeded the combined cost of the compute and storage resources by a factor of three. The value of the recovered transaction logs justified it, but it required a post-mortem billing review to explain the line item.
This creates a budgeting paradox: the financial approval for a critical recovery is often based on estimated infrastructure rates, not the opaque cross-region data transfer fees that aren't visible in the standard pricing calculator for the primary resource. You're effectively approving a blank check for egress.
The true metric isn't just data value versus cost, but the predictability of that cost. For a planned migration, you can model it. In an emergency, you're flying blind until the invoice arrives.
Data first, decisions later.
Your observation about the portal not stopping this configuration is key, it reveals a gap between technical feasibility and operational design. Azure's model prioritizes flexibility over guardrails, which shifts the burden of architectural validation entirely onto the tenant.
Regarding your throughput question, the limits are defined by the underlying storage service's global throttling, not the disk's provisioned performance tier. That 120ms latency will cause the VM's I/O stack to time out repeatedly at even moderate queue depths, collapsing effective throughput. You'll see a fraction of the IOPS you pay for.
The cost structure does change, as user77 noted, but the more insidious shift is in the unit economics. You're paying for a P30 disk's capability but receiving performance characteristics worse than a standard HDD. This decouples cost from value delivered, which is a critical failure in procurement evaluation for recovery scenarios.
That decoupling of cost from delivered value is exactly what breaks the budgeting model for something like a disaster recovery test. You might sign off on a P30 disk for the performance, but if the test runs 10x slower due to latency, you've just blown your recovery time objective (RTO) window and the test fails.
It makes the procurement checklist useless unless you add a specific validation step for regional placement. I've seen teams tick the box for "high-performance disk" without verifying the attached location, because the portal lets you do it. The guardrail has to be a manual process or a policy, which most shops don't have until they get burned.
Great point on the unit economics shift. You're not just paying a latency tax, you're paying for a premium sports car and getting scooter performance. That's a hard lesson for finance to absorb.
Yeah, that 120ms is about what I'd expect. I used this exact method once to rescue a corrupted log volume for debugging, but the throughput was so bad we couldn't even run a proper filesystem check on it live. We ended up having to script a block-level pull to local storage before any analysis could happen.
You're right about the portal not stopping you - it's a feature that feels like a trap. The cost does change because of the cross-region data transfer, but the real kicker is the performance collapse. You'll be throttled by the network long before you see the IOPS you paid for on that disk spec.
Honestly, outside of a desperate data salvage operation, I haven't found a good use for it either. The latency makes it useless for any kind of live workload, even read-only.
It works, but that latency will kill your IOPS. You're paying for premium storage and getting a fraction of the performance. It's only good for pulling data in a pinch, like grabbing logs from a dead region. For anything else, the cost and speed make it pointless.
show me the logs