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SSDs have become fast, except in the cloud

(databasearchitects.blogspot.com)
589 points greghn | 4 comments | | HN request time: 0.782s | source
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wistlo ◴[] No.39453430[source]
At my job at a telco, I had a 13 billion record file to scan and index for duplicates and bad addresses.

Consultants brought in to move our apps (some of which were Excel macros, others SAS scripts running on old desktop) to Azure. The Azure architects identified Postgres as the best tool. Consultants attempted to create a Postgres index in a small Azure instance but their tests would fail without completion (they were string concatenation rather than the native indexing function).

Consultants' conclusion: file too big for Postgres.

I disputed this. Plenty of literature out there on Pg handling bigger files. The Postgres (for Windows!) instance on my Core I7 laptop with an nVME drive could index the file about an hour. As an experiment I spun up a bare metal nVME instance on a Ryzen 7600 (lowest power, 6 core) Zen 4 CPU pc with a 1TB Samsung PCIe 4 nVME drive.

Got my index in 10 minutes.

I then tried to replicate this in Azure, upping the CPUs, memory, and to the nVME Azure CPU family (Ebsv5). Even at a $2000/mo level, I could not get the Azure instance any faster than one fifth (about an hour) of the speed of my bare metal experiment. I probably could have matched it eventually with more cores, but did not want to get called on the carpet for a ten grand Azure bill.

All this happened while I was working from home (one can't spin up an experimental bare metal system at a drop-in spot in the communal workroom).

What happened next I don't know, because I left in the midst of RTO fever. I was given the option of moving 1000 miles to commute to a hub office, or retire "voluntarily with severance." I chose the latter.

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bcaxis ◴[] No.39454045[source]
This matches my experience. Something about cloud systems makes them incredibly slow compared to real hardware. Not just the disk, the CPU is more limited too.

I fire up vCPU or dedicated or bare metal in the cloud, doesn't matter, I simply cannot match the equivalent compute of real hardware and it's not even close.

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1. silent_cal ◴[] No.39454359[source]
Isn't that expected? I would assume cloud stuff is slower because it's essentially an emulation of the real thing.
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2. pdimitar ◴[] No.39459637[source]
Why should it be expected? I'm being sold compute with quoted GHz CPU speeds, RAM and types of SSDs.

I would vaguely expect it to not match my workstation, sure, but all throughout this thread (and others) people have cited outrageous disparities i.e. 5x less performance that you'd expect even if you managed your expectations to e.g. 2x less due to the cloud compute not being a bare metal machine.

In other words, and to illustrate this with a bad example: I'd be fine paying for an i7 CPU and ending up at i5 speeds... but I'm absolutely not fine with ending up at Celeron speeds.

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3. bcaxis ◴[] No.39460997[source]
When I spin up a vm on my hardware and run an application. The performance is generally about 70% of what I can get in a container running on an OS on that very same bare metal.

But that isn't the delta I'm seeing, it's 5-10x performance delta not a 30-50% delta.

4. silent_cal ◴[] No.39468050[source]
Makes sense.