fixed posts, got rid of sample posts

1 files changed, 0 insertions, 95 deletions

diff --git a/generations.md b/generations.md
deleted file mode 100644
index d36b175..0000000
--- a/generations.md
+++ /dev/null
@@ -1,95 +0,0 @@
-# Generations
-
-A simple file distribution strategy for very large scale, high-availability
-file-services.
-
-# The problem
-
-Working at a shop where we have millions of different files, any of which could
-be arbitrarily chosen to serve to a file at any given time. These files are
-uploaded by users of the app and retrieved by others.
-
-Scaling such a system is no easy task. The chosen solution involves shuffling
-files around on a nearly constant basis, making sure that files which are more
-"popular" are on fast drives, while at the same time making sure that no drives
-are at capicty and at the same time that all files, even newly uploaded ones,
-are stored redundantly.
-
-The problem with this solution is one of coordination. At any given moment the
-app needs to be able to "find" a file so it can give the client a link to
-download the file from one of the servers that it's on. Full-filling this simple
-requirement means that all datastores/caches where information about where a
-file lives need to be up-to-date at all times, and even then there are
-race-conditions and network failures to contend with, while at all times the
-requirements of the app evolve and change.
-
-# A simpler solution
-
-Let's say you want all files which get uploaded to be replicated in triplicate
-in some capacity. You buy three identical hard-disks, and put each on a separate
-server.  As files get uploaded by clients, each file gets put on each drive
-immediately. When the drives are filled (which should be at around the same
-time), you stop uploading to them.
-
-That was generation 0.
-
-You buy three more drives, and start putting all files on them instead. This is
-going to be generation 1. Repeat until you run out of money.
-
-That's it.
-
-## That's it?
-
-It seems simple and obvious, and maybe it's the standard thing which is done,
-but as far as I can tell no-one has written about it (though I'm probably not
-searching for the right thing, let me know if this is the case!).
-
-## Advantages
-
-* It's so simple to implement, you could probably do it in a day if you're
-starting a project from scratch
-
-* By definition of the scheme all files are replicated in multiple places.
-
-* Minimal information about where a file "is" needs to be stored. When a file is
-uploaded all that's needed is to know what generation it is in, and then what
-nodes/drives are in that generation.
-
-* Drives don't need to "know" about each other. What I mean by this is that
-whatever is running as the receive point for file-uploads on each drive doesn't
-have to coordinate with its siblings running on the other drives in the
-generation. In fact it doesn't need to coordinate with anyone. You could
-literally rsync files onto your drives if you wanted to. I would recommend using
-[marlin][0] though :)
-
-* Scaling is easy. When you run out of space you can simply start a new
-generation. If you don't like playing that close to the chest there's nothing to
-say you can't have two generations active at the same time.
-
-* Upgrading is easy. As long as a generation is not marked-for-upload, you can
-easily copy all files in the generation into a new set of bigger, badder drives,
-add those drives into the generation in your code, remove the old ones, then
-mark the generation as uploadable again.
-
-* Distribution is easy. You just copy a generation's files onto a new drive in
-Europe or wherever you're getting an uptick in traffic from and you're good to
-go.
-
-* Management is easy. It's trivial to find out how many times a file has been
-replicated, or how many countries it's in, or what hardware it's being served
-from (given you have easy access to information about specific drives).
-
-## Caveats
-
-The big caveat here is that this is just an idea. It has NOT been tested in
-production. But we have enough faith in it that we're going to give it a shot at
-cryptic.io. I'll keep this page updated.
-
-The second caveat is that this scheme does not inherently support caching. If a
-file suddenly becomes super popular the world over your hard-disks might not be
-able to keep up, and it's probably not feasible to have an FIO drive in *every*
-generation. I think that [groupcache][1] may be the answer to this problem,
-assuming your files are reasonably small, but again I haven't tested it yet.
-
-[0]: https://github.com/cryptic-io/marlin
-[1]: https://github.com/golang/groupcache