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Comment by defunkt | Hacker News Reader

Rather than do the re-architecture now, they've chosen instead to move to a vendor who can provide them a high performance, high availability, non-commodity, proprietary network file server infrastructure. I suspect it will work well for them, and we'll all enjoy a faster Github. :-)

GitHub has been working on a re-architecture since our last major feature release, which was GitHub Issues in April.

And we can't wait to roll it out.

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Great news, Chris, sorry to misrepresent.

So, the new Github architecture is shared nothing?

So, the new Github architecture is shared nothing?

This is a pet peeve of mine -- what does "shared nothing" even mean?

A database, a "NoSQL" key store, and memcached are all sharing something, and that something is a contention point.

Specifically in this context, how do you implement transactional SCM semantics without sharing something (such as a distributed lock system?).

Shared nothing usually means that each node in a system shares no source data with any other node, it has it's own discrete database/disk/etc. However, these systems commonly share a communication link, so they can tell eachother about changes made on their database/disk etc. With a truly shared nothing platform, an entire node can go down and all of the other nodes continue to operate normally (except from the increase in load as users are migrated from the dead system to the live systems).

The bad part about shared nothing is quite simple, it's damn hard to do, and harder to get right. One of the biggest problems is handling conflicting data between nodes. You either have to handle the conflict with your application, or your database needs to automatically choose the best copy (based on date etc).

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