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This has been my exact field of work for a few years now; in general I have found that: When people claim it is 10x more expensive to use public cloud, they ha

This has been my exact field of work for a few years now; in general I have found that: When people claim it is 10x more expensive to use public cloud, they have no earthly idea what it actually costs to run a HPC service, a data centre, or do any of the associated maintenance. When the claim is 3x more expensive in the cloud, they do know those things but are making a bad faith comparison because their job involves running an on-premises cluster and they are scared of losing their toys. When the claim is 0-50% more to run in the cloud, someone is doing the math properly and aiming for a fair comparison. When the claim is that cloud is cheaper than on-prem, you are probably talking to a cloud vendor account manager whose colleagues are wincing at the fact that they just torched their credibility.

lebovic 4y ago
Author here! I think running an HPC service that has a steady queue in AWS can be more than 3x as expensive. What type of HPC do you work in? Maybe I'm over-indexing on computational biology.
- Moissanite 4y ago
  All types of HPC; I'm a sysadmin/consultant. I don't think the problem with the cost gap is overestimating cloud costs but rather underestimating on-prem costs. Also, failing to account for financing differences and opportunity-costs of large up-front capital purchases.
johnklos 4y ago
This is oversimplifying things a bit. It can categorically be stated that for a year's worth of CPU compute, local will always be less than Amazon. Of course, putting percentages on it doesn't work - there are just too many variables. There are many admins out there who have no idea what an Alpha is who'll swear that if you're not buying Dell or HP hardware at a premium with expensive support contracts, you're doing things wrong and you're not a real admin. Visit Reddit's /r/sysadmin if you want to see the kind of people I'm talking about. The point is that if people insist on the most expensive, least efficient type of servers such as Dell Xeons with ridiculous service contracts, the savings over Amazon won't be large. It's a cumulative problem, because trying to cool and house less efficient hardware requires more power and that hardware ultimately has less tolerance for non-datacenter cooling. Rethink things. You can have AMD Threadripper / EPYC systems in larger rooms that require less overall cooling, that have better temperature tolerance, that're more reliable in aggregate, which cost less and for which you can easily keep around spare parts which would give better turnaround and availability than support contracts from Dell / HP. Suddenly your compute costs are halved, because of pricing, efficiency, overall power, real estate considerations... So percentages don't work, but the bottom line is that when you're doing lots of compute, over time it's always cheaper locally, even if you do things the "traditional" expensive and inefficient way, so arguing percentages with so many variables doesn't make any sense - it's still cheaper, no matter what.

lebovic 4y ago

Author here! I think running an HPC service that has a steady queue in AWS can be more than 3x as expensive. What type of HPC do you work in? Maybe I'm over-indexing on computational biology.

Moissanite 4y ago
All types of HPC; I'm a sysadmin/consultant. I don't think the problem with the cost gap is overestimating cloud costs but rather underestimating on-prem costs. Also, failing to account for financing differences and opportunity-costs of large up-front capital purchases.

johnklos 4y ago

This is oversimplifying things a bit. It can categorically be stated that for a year's worth of CPU compute, local will always be less than Amazon. Of course, putting percentages on it doesn't work - there are just too many variables. There are many admins out there who have no idea what an Alpha is who'll swear that if you're not buying Dell or HP hardware at a premium with expensive support contracts, you're doing things wrong and you're not a real admin. Visit Reddit's /r/sysadmin if you want to see the kind of people I'm talking about. The point is that if people insist on the most expensive, least efficient type of servers such as Dell Xeons with ridiculous service contracts, the savings over Amazon won't be large. It's a cumulative problem, because trying to cool and house less efficient hardware requires more power and that hardware ultimately has less tolerance for non-datacenter cooling. Rethink things. You can have AMD Threadripper / EPYC systems in larger rooms that require less overall cooling, that have better temperature tolerance, that're more reliable in aggregate, which cost less and for which you can easily keep around spare parts which would give better turnaround and availability than support contracts from Dell / HP. Suddenly your compute costs are halved, because of pricing, efficiency, overall power, real estate considerations... So percentages don't work, but the bottom line is that when you're doing lots of compute, over time it's always cheaper locally, even if you do things the "traditional" expensive and inefficient way, so arguing percentages with so many variables doesn't make any sense - it's still cheaper, no matter what.