Networks will improve?
Network latency: plausible within 5 years?
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The latency goal should be from the web app perspective. Google and Facebook want distributions, not goals.—
2-second recovery is fast enough?
7 or so people think 2 second hiccups are OK. Think end-to-end: stupid DNS server, etc.
Facebook wants a tryGet() - try to get and if it takes too long, abort. Might be useful when a 2s hiccup is not ok.
How many apps are there nowadays that don't tolerate 2s hiccups?
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Facebook: Crucial piece of metadata on some server, every web machine waits for 2s, systemic fallout from that.
tryGet() with exponential backupbackoff, application-level replication.
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How often does it happen? How global is the effect?—
Per-server battery backups will become available?
Google: distinction (for recovery) between in-flight data and data that was written over half an hour ago. Much more important not to lose old data.
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Google: Do you store ramcloud state in ramcloud itself?
Losing pointers to say a partition may lose the entire partition.—
Low latency will make a big difference?
Google: I think you're right. People that run their services today will say "Oh it's not going to help us"
"It will be a lot easier to develop applications that you could have developed with higher latency"
It might come down to the cost.—
Low latency will enable stronger consistency at scale?
You have consistency problems with main memory, it's not like that problem is gone.
You're trying to allow people to increase R.
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Sinfonia: There's a cross-section: # object locked * amount of time should be fairly small—
Locality is getting harder to find and exploit?
In any system when you have 100M users, thinks there will be low locality.
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Graph algos have phases: local computation, then batch updates to other machine.
No Not clear on optimizing the "local computation" phase, that's going to cause a lot of bandwidth.
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Google: Could say: Let's assume someone gives us a distributed file system to store all the log files. How can we get the latency down?
John: Is there such a filesystem in existence?
Google: Conceptually, I don't see what the difference is between your writes and those of hadoopfs or gfs.
They scatter things across.
It could be that you don't really want to deal with their implementations.
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