I mean you must have one logical master - multimaster fixes this to a degree.
MogileFS in its current design _must_ only talk to one database or else its locking scheme doesn't work. We use multimaster databases with heartbeat to ensure all trackers are talking to a single database at any time. Unfortunately (right now, anyway...) you can't have the trackers just talk to the local database on each side. -Dormando Arnoud Vermeer wrote: > You can use a mysql master-master setup to solve the problem of the > single database. The trick is to use auto_increment_increment and > auto_increment_offset so that you're auto_increment never gets screwed > up. You can find really good documentation on onlamp.com > <http://onlamp.com/> under advanced mysql replication*. I use the > following settings: auto_increment_increment = 10 > auto_increment_offset = 1 on db10 and auto_increment_increment = 10 > auto_increment_offset = 2 on db20. This means you can scale to a > replication ring of max 10 nodes. > > You make one master at datacentre 1 and the other at datacentre 2. Let > all the mogilefsd's connect to the local database or use heartbeat to > switch them over. > > * > http://www.onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html > > Arnoud Vermeer > > On Thu, May 22, 2008 at 1:37 AM, dormando <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > > MogileFS does replication between datacenters. There's still a > single database, but you can work with that a bit. > > In trunk there's code but no documentation for it. Basically you > configure network zones, then use a specific replication policy to > say how many copies you want in each network. The trackers will > return paths "local" to that client. > > There're no docs yet, but we run it in production and it works okay. > Fixes/updates coming, and it's not hard to set up if you want to > test it in a dev setup. > > Also, we got your mail three times :) > > -Dormando > > > William Francis wrote: > > * sorry if this comes through more than once. I sent a few hours ago > but it hasn't shown up on the list yet. gmail's IMAP has been weird > today :-/ > > > We currently have mogilefs running quite satisfactorily for our > service and we're growing into a second datacenter initially for > disaster recovery but eventually load balancing as well. After a > couple hours of searching and looking through CPAN I've noticed that > geographic replication seems to be something that has been discussed > several times in the past (here and elsewhere) but I've been > unable to > locate anything that suggests the best approach to take for our > situation. Did I miss something or is this still in the realm > of 'gee > that'd be neat' but there's no generally accepted way to do it and > it's just been hacked together somehow each time by people who > need to > solve this problem? > > Any pointers greatly appreciated and thanks for something that works > beautifully! > > Will > > >
