[Systems] migrating to beam rider

[David Farning]

On Tue, Oct 20, 2009 at 4:16 AM, Tomeu Vizoso <tomeu at sugarlabs.org> wrote:
> On Tue, Oct 20, 2009 at 07:04, Bernie Innocenti <bernie at codewiz.org> wrote:
>> El Mon, 19-10-2009 a las 22:01 -0500, David Farning escribió:
>>
>>> If this is hard, we can post pone it until later and just copy the
>>> directories.  The advantage of setting up the common mount point now
>>> is that we can share a common database instance, memcache instance,
>>> and file directories.  By doing this, we can point activities2.sl.o at
>>> beamrider for testing.  From a user pov a.sl.o and a2.sl.o will be
>>> exactly the same.  To go live we just need to flip a switch to point
>>> a.sl.o from sunjammer to beam rider.
>>
>> We can do it, but truly scalable and fault-tolerant architectures
>> are supposed to be "shared nothing". Or "share as little as required
>> for consistency". Perhaps we could get along with sharing just the
>> database.
>
> What I remember from the code, is that there was a local read-only db
> instance per machine, and a read-write instance that was shared by
> all.

There are two databases, a primary database and a shadow database.  I
need to go though  the code again to figure out how they interact.

david

> Regards,
>
> Tomeu
>
> --
> «Sugar Labs is anyone who participates in improving and using Sugar.
> What Sugar Labs does is determined by the participants.» - David
> Farning
>