

New Open Source Cache System - ajbatac
http://highscalability.com/ann-new-open-source-cache-system

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mdasen
They have a comparison to different caching solutions, but don't really have
an explanation of it. For example, they say that they handle any size data
(vs. memcached which allocates specific size blocks stopping at 1MB). I know
that memcached does that because using a normal memory management structure
that would give them that any size flexibility would cause the operating
system to have to deal with the fragmentation that comes with that and dealing
with that fragmentation takes a lot of time.

Likewise, storing to disk takes time rather than just storing in memory. Even
if you store the objects in memory as well, writes are slower even though
reads should be the same. A caching server shouldn't need its data to survive
a crash since the authoritative copy should be in the database.

They're also quoting 20,000 transactions per _minute_ depending on hardware.
That doesn't seem that good. Considering that memcached handles 50,000
requests per _second_ in its stock form or 200,000 requests per seocond with
Facebook's modified version, 333 "transactions" per second doesn't sound so
great. Maybe "transaction" is something other than a request for an object
(maybe it's saving objects which sccache isn't optimized for).

It looks really cool, but before I would consider it I would want to know more
about how it allocates memory and why they made some of the design decisions
they made. I know that memcached put in its limitations in order to make it
ultra fast and ultra scalable.

