How to maintain cache update on different memcached servers?

[howard chen]

On 11/1/06, Andrew Pile <andrew at connectedventures.com> wrote:
> That is NOT how it works. The data is not stored evenly on all
> servers, it is hashed and sent to one server.
>
> On Oct 31, 2006, at 11:26 AM, Jehiah Czebotar wrote:
>
> >> so, correct me if i am wrong...
> >>
> >> 1. on each memcached server, i start the memcached deamon as they are
> >> separetely server, they don't know each other, e.g.
> >> ./memcached -d -m 2048 -l 10.0.0.40 -p 11211
> >>
> >> 2. during connection from client, add all the servers...
> >> e.g.
> >>
> >> $memcache = new Memcache;
> >> $memcache->addServer('memcache_host', 11211);
> >> $memcache->addServer('memcache_host2', 11211);
> >>
> >> 3. the memcached objects will be stored evenly on all these server,
> >> and i can get it using Memcache::get , without specifying the server
> >> host
> >>
> >
> > correct: that is exactly it.
> >
> > (just make sure the memory you are configuring memcached to use (2048)
> > is not larger than the actuall free RAM on your machines)
> >
> > --
> > Jehiah
>
>

yes, this is the point, how does hashing work?

e.g.

originally three servers, A, B, C

an object is hashed to server B

but server B was downed, and it will hashed to server C when receive
another request ? what will happen if server B up again?