memcached replication

[hirose31 at t3.rim.or.jp]

Hello,

Oh, I am also working for memcached replication.

  - asynchronous repliacation. (like MySQL)
  - single master, single slave.
  - slave connect to master.
  - sequence:
    - client requests SET command to master
    - push key to queue
    - pop key from queue (asynchronous)
    - fetch value for key
    - send key/value to slave by memcached protocol
  - when new slave connect to master, master copy whole data to slave.

My main purpose is:
  - redundancy memcached system
  - safe fail over
not scalability, or high performance.

I will release first alpha in this month. :-)


in "Re: memcached replication"
   <4cf2912c0708282312l16ec38dfm991bd601e7c884d7 at mail.gmail.com>
at Wed, 29 Aug 2007 11:42:19 +0530,
   venkatesh.ks at gmail.com wrote:

> [1  <text/plain; ISO-8859-1 (7bit)>]
> I am working on something similar.
> 
> I am trying the following.
> 
> 1. Convert memcached to inprocess cache. There is going to be a socket
> through which it can still talk
> but it can also do bypass calls down to memcached routine.
> 
> 2. Memcached to notify if a cache entry expires or is ejected. This
> notifiction for now is just a function pointer (this will help
> me cleanup some state) but in could event notified over n/w to interested
> parties.
> 
> Infuture I may go towards inprocess cache as L1 and out of process L2 cache.
> The L2 can reside out of box as well. The L2 could be used by many L1 caches
> as well. And L1 can just cache information about L2 entries. And if there is
> a way for L2 (memcached) to notify events (add/eject/delete) to the
> interested parties.
> 
> 
> -venkatesh
> 
> 
> 
> On 8/29/07, Matt Ingenthron <Matt.Ingenthron at sun.com> wrote:
> >
> > Marcus Bointon wrote:
> > > On 29 Aug 2007, at 00:37, Dustin Sallings wrote:
> > >
> > >> My goal is not replication, but to allow for a sort of L1 cache in an
> > >> application with memcached as an L2 and cache invalidation service.
> > >
> > > That's a really nice idea. I've seen something vaguely similar with
> > > jgroups, but it lacks the best bits of both memcache and in-process
> > > caches (I'm also using APC with PHP). I can see that being a very
> > > efficient system.
> >
> > That's also what ehCache does (in process cache, with remote L2 cache)
> > for Java applications.
> >
> > I've looked at it a bit and talked with Greg Luck about it (the night he
> > released his "benchmark" between ehCache and memcached).  The
> > "benchmark" shows an impressive chart but leaves out the details you
> > really need to understand what's going on-- looks like his blog filled
> > in the details.
> >
> > Personally, I see room for both approaches.  From discussions with
> > others, there are times you just want an app to minimize local memory
> > usage.  Plus, in talking with Greg, he specifically plans in most cases
> > to have a cache that overflows OS page buffer, which tells you it's
> > typically deployed in a different way than memcached.  That doesn't
> > negate the fact that sometimes a well managed, in-process cache would be
> > an advantage.
> >
> > - Matt
> >
> > --
> > Matt Ingenthron - Web Infrastructure Solutions Architect
> > Sun Microsystems, Inc. - Global Systems Practice
> > http://blogs.sun.com/mingenthron/
> > email: matt.ingenthron at sun.com             Phone: 310-242-6439
> >
> >
> [2  <text/html; ISO-8859-1 (7bit)>]
> 

-- 
HIROSE, Masaaki