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Migrating Uber's ledger data from DynamoDB to LedgerStore

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Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#291

Post by nikolajan »

amluto wrote: post #286
crmd wrote: post #265

Earlier quoted context omitted.

The primary use case is not analytics. This data store is the system of record in their credit card authorization and billing pipeline, and so it has extreme consistency requirements. The lion’s share of its engineering is to provide consistency across a large spectrum of failure modes. Old data could probably live at lower cost in a data warehouse, but then developers would have multiple systems and namespaces to de…

> This data store is the system of record in their credit card authorization and billing pipeline, and so it has extreme consistency requirements. This seems like an odd requirement to me. What are the use cases beyond a few minutes past the end of the ride? - Reconciliation of Uber's finances. This definitely needs to be correct and consistent and maybe even auditable, but it's also done at the end of any given bill…

>This seems like an odd requirement to me. What are the use cases beyond a few minutes past the end of the ride?

Exactly what he the OP said, authorization. Card networks cap latency of authorization requests (the time the merchant submits a request, to when it makes its make through the merchant processor, networks, issuer processor and back.)

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#292

Post by nikolajan »

8ytecoder wrote: post #282
crmd wrote: post #265

Earlier quoted context omitted.

The primary use case is not analytics. This data store is the system of record in their credit card authorization and billing pipeline, and so it has extreme consistency requirements. The lion’s share of its engineering is to provide consistency across a large spectrum of failure modes. Old data could probably live at lower cost in a data warehouse, but then developers would have multiple systems and namespaces to de…

Which is …normal. Different types of data access have different SLA requirements. Any company that cares about cost will warehouse data after x time frame. It’s done even in banking. Uber has a much more lenient need to make this data instantly available.

> It’s done even in banking

What are you basing this on, banks have less real time constraints when it comes to certain data but thats rare. You will almost never see a bank, processor, etc. archive their system of record data.

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#294

Post by fhsm »

scarface_74 wrote: post #172
gtirloni wrote: post #89

Earlier quoted context omitted.

If anything, it reduces Uber's exposure to AWS' proprietary technology. I don't know how to measure how much that's worth but they probably do.

This usually comes from people who have never done a mass migration at scale. You’re always dependent on your infrastructure. Even if you have nothing but everything hosted on a bunch of VMs, it can take years and millions of dollars to migrate. No, just use Terraform and Kubernetes is not the answer. The typical enterprise is dependent on depending on the source between 80 - 120 SaaS products - ie outside vendors.

Indeed. Everyone enjoying the Broadcom / VMWare situation is running around saying how glad they are that it’s “just a bunch of VMs” and this migration will be a walk in the park.

It could be worse. It could be better.

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#295

Post by danpalmer »

xyst wrote: post #185

Uber must have picked up some Google rejects. This type of homegrown project was seen at Google all the time. Usually to aim for a significant promotion. “Designed and built homegrown system to save $Xm! Give me promo, bro?” Just so happened to ignore that it took X+Y additional to build. Also it will probably be going to the G graveyard in a few years.

I'm not sure if this is true of modern Google. Certainly there are a ton of custom things around, but it also seems like in the last 5 years there has been a huge push towards not re-inventing more databases/etc, and normalising everything onto a few core technologies. A good example is Spanner, many products have been moved off other home-grown systems onto Spanner, basically to reduce complexity and cost. Sure Spanner is a Google technology, but at least it's one, instead of having all sorts of different esoteric systems, and Spanner is just one example, this is happening in a number of different domains.

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#296

Post by ndriscoll »

hallway_monitor wrote: post #287
perryh2 wrote: post #235

Earlier quoted context omitted.

Supermicro https://www.supermicro.com/en/products/nvme?pro=formfactor%3...

Shows 2U in order to fit 32 drives, but hopefully you can find a 2U slot for this absolute monster of a storage box if you have that need.

This one is 1U and supports dual socket CPU and 6 TB RAM:

https://www.supermicro.com/en/products/system/1U/1029/SSG-10...

I've never done procurement so can't really speak to recommendations. I just see that the products apparently exist.

There's also 32 drive 1U JBOF enclosures for more expansion:

https://www.supermicro.com/en/products/system/1u/136/ssg-136...

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#297

Post by omeid2 »

Retric wrote: post #136
omeid2 wrote: post #123

Earlier quoted context omitted.

There is no upper bounds to economy of scales. Maybe there is for the cents per GB of raw storage, but power usage, security, rent, and everything else scales too, and few of them have upper bounds on economy of scales.

Economies of scale generally have upper limits. Often when you approach the largest scale the existing market will supply you essentially need to become your own supplier which then runs into span of control issues. The organization needs to become competitive in that new market or their costs increase. Keep scaling and eventually vertical integration ends up looking like a Soviet style planned economy. Your remote m…

Yes, there is an upper limit, and that is the entirety of global economy. But that assertion is as useless as it is true.

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#298

Post by RobRivera »

leoqa wrote: post #208
cj wrote: post #198

Earlier quoted context omitted.

$6m in annual cost savings is truly unremarkable, if we are to believe levels.fyi [0] [1] If you're truly paying engineers, project managers, etc $500k a head, it dramatically undermines the financial cost savings. It very well might be the case that "We spent $25m of engineering resources to save $6m annually". [0] https://www.levels.fyi/companies/uber/salaries/software-engi... [1] https://www.levels.fyi/companies/u…

Bitter story time: I made a config change to our AWS instances and projected approximately $10MM/year in AWS costs savings (pre-savings). My boss asked me "Who told you to do this? We need to focus on $project instead". I found another team and transferred out. 3 months later there was a big fire drill about AWS costs and they took my 1-pager and executed it. Didn't get any credit in the shipped email nor did the man…

Sounds like a fantastic way to maneuver and get credit for someone else's proactive engenuity

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#299

Post by sa46 »

geodel wrote: post #154
theanirudh wrote: post #11

I wonder if they considered https://tigerbeetle.com

Would be interesting. Considering TigerBeetle is written in Zig. And Uber is probably only rare big company which has support contract with Zig foundation.

One interesting caveat is that Uber only uses the Zig toolchain, not the Zig language.

https://www.uber.com/en-US/blog/bootstrapping-ubers-infrastr...

Re: Migrating Uber's ledger data from DynamoDB to LedgerStore

#300

Post by nostrebored »

noncoml wrote: post #254
heavenlyblue wrote: post #233

Earlier quoted context omitted.

Of course you didn't. You used your time to promote yourself instead of doing what you were asked to do instead. That could have cost a promotion for your manager who could have promoted you.

I don’t know you are downvoted. Aligning the personal interest vector with the companies interest vector is a huge problem that is usually underrepresented in NH comments. Usually we only complain about the short sighting of the CEOs that prioritize short term stock gains over long term prosperity, but that also is just a specialized case of the success vector misalignment

This is a poor way to view salaried work.

If OP is meeting deliverables and did this on the side, this is a great example of a story that would make me inclined to hire.

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