I deal with dozens of systems, all doing cross-country or cross-ocean replication. The only viable approach (that we have deployed in production) is * Dual-master, single writer -- That is, all 49 clients write to one machine * The two masters are geographically separate. * Failover involves switching to the 'other' master. It is _not_ fully automated. * Slaves, as needed, scattered around the world -- This provides read scaling.
1M writes per day -- that is an average of 12/sec. Yawn. Replication delay -- you probably will almost never see any. Network outages -- one of many things that can cause trouble. The sooner you write the data _and_ copy it to a _remote_ site, the sooner you are immune to floods, tornados, cyclones, power outages, motherboard death, etc. > -----Original Message----- > From: Anupam Karmarkar [mailto:sb_akarmar...@yahoo.com] > Sent: Thursday, May 24, 2012 3:39 AM > To: Nigel Wood > Cc: mysql@lists.mysql.com > Subject: Re: Architectural Help > > Dear Nigel, > > Thank for reply.. > > > See my comments below > > > --Anupam > > > ________________________________ > From: Nigel Wood <nw...@plus.net> > To: Anupam Karmarkar <sb_akarmar...@yahoo.com>; "mysql@lists.mysql.com" > <mysql@lists.mysql.com> > Sent: Thursday, 24 May 2012 3:35 PM > Subject: RE: Architectural Help > > A few questions: > which is more or a problem: network outages, network capacity or query > latency? > >>Network Outages is problem, between data centres > When you say "near real-time" do you need transactional consistent view > on all 49 servers or can some lag be tolerated? > >>Some lag can be tolerated considering network outage > Can any one of the 49 local servers potentially update/delete the same > rows or data? > >>Yes central server can update same row or local server but not at > same time, Few data will be updated in central location and others > majorly in local.One Application Writes in Centeral and Others in > local, Local app and central app shares some data. > Is there any natural segmentation point within the data? > >>No > Do the data centers have diverse networks so that connections to some > data centers may remain when others? > >>Yes, we have diverse nework , so connectivity will be avaiable in > other data centers. > In the event that a local data centre is totally isolated from the > others what data should it be allowed to update? > >>Loca application should always write in local database, Central > Application Updated will not be available to local. > Do your applications produce/examine large data set querying by > secondary keys or using tull text search? > >>We dont have text search or we dont query large data > Are you in a position to modify the applications? > >>No, Micro changes ok > __________________________________ > From: Anupam Karmarkar [sb_akarmar...@yahoo.com] > Sent: Thursday, May 24, 2012 10:17 AM > To: mysql@lists.mysql.com > Subject: Architectural Help > > Hi All, > > > I need architectural help for our requirement, > > > We have nearly 50 data centre through out different cities from these > data center application connect to central database server currently, > there are conectivity and nework flcutions issues for different data > center, so we comeup with solution each data center we should have > local database server which will keep syncing with other server so that > application doesnt fail , User data can be updated in any of server and > should reflect in every server. Application consists of > write/read/delete operations, > > > Current writes each day central server 1million. > > > Only 1/1000 need to be distrubuted acrross servce rest need to be in > central server. > > > How can we achive this ? solution needs very much real time data > accepting nework lags. > > > Solution > > Collect all changes in other 49 server into 1 central server(How can we > collect data) > > > 49 keeps updating data into local database from central server(Using > Repliation Can be done) > > > > --Anupam > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql To unsubscribe: > http://lists.mysql.com/mysql -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
