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> the recruiter indicated I had a magic datacenter that did not have problems with cross-connecting many, many hundreds of GB/s in a mesh Well, then this is d

> the recruiter indicated I had a magic datacenter that did not have problems with cross-connecting many, many hundreds of GB/s in a mesh Well, then this is different than your original description, I'd need to get more details about the problem but he is right that machine to machine connections in a data center doesn't scale very well. This might not be a problem at the scales you are used to but it is a problem at Google scale. This is a very common problem that is not obvious at first when you work with data centers, I guess he just assumed that you would know this. Knowing your background you would probably adapt to it quickly on the job, but I guess they just asked the same question to every experienced SRE they got? Edit: Another problem with your solution is that you used a static sharding strategy and didn't consider that increasing demand in the future would force you to reshard the database. Downtime might be accepted in the video game industry, and there you most likely wont even get much more demand than day 1, but using sharding strategies which lets you reshard in real time without downtime is more or less a must on the projects I worked on.

dijit 7y ago
I had previously asked about load and the interviewer said that it would not grow. However that was a very real drawback in my design.
- username90 7y ago
  Ok, then I guess he just kept quiet about the intra datacenter bandwidth issue during the interview. Personally I'd have told you and discussed it, worst case I'd recommend down leveling stating that you don't have enough experience with systems at this scale but could be a good candidate otherwise, but I probably wouldn't have rejected you outright due to it. But hey, not every interviewer can be reasonable.
  - dijit 7y ago
    I don’t believe the interviewer wasn’t reasonable. I gathered as many requirements as I could and gathered as much info about my constraints as I could and thought up a solution on the spot. It wasn’t perfect and I was rushing through calculus that I would normally spend a lot of time validating. The interviewer probably saw my use of technology as a cop-out and wanted to challenge it. When I told him why I chose it he probably just took it as unwillingness to change my position. It is very possible that I poorly communicated the fact that my position was completely mutable. EDIT: the magic datacenter was the interviewer removing that as a constraint. I did not indicate that _I_ had a magic datacenter and I kept challenging the limits of networking, which was handwaved away.

dijit 7y ago

I had previously asked about load and the interviewer said that it would not grow. However that was a very real drawback in my design.

username90 7y ago
Ok, then I guess he just kept quiet about the intra datacenter bandwidth issue during the interview. Personally I'd have told you and discussed it, worst case I'd recommend down leveling stating that you don't have enough experience with systems at this scale but could be a good candidate otherwise, but I probably wouldn't have rejected you outright due to it. But hey, not every interviewer can be reasonable.
- dijit 7y ago
  I don’t believe the interviewer wasn’t reasonable. I gathered as many requirements as I could and gathered as much info about my constraints as I could and thought up a solution on the spot. It wasn’t perfect and I was rushing through calculus that I would normally spend a lot of time validating. The interviewer probably saw my use of technology as a cop-out and wanted to challenge it. When I told him why I chose it he probably just took it as unwillingness to change my position. It is very possible that I poorly communicated the fact that my position was completely mutable. EDIT: the magic datacenter was the interviewer removing that as a constraint. I did not indicate that _I_ had a magic datacenter and I kept challenging the limits of networking, which was handwaved away.