Migration from SQL Server 2000 to 2012 without Outage -


i working on project migrating legacy sql server 2000 instances sql server 2012. read word legacy, these databases used vb based desktop applications. has around 4000+ users , application rated gold (means has 24x7)

summary again

  • desktop exe installed vb applications -> sql server 2000

target state

  • desktop exe installed vb applications -> sql server 2012

application uses config file contains sql server details connects to. once data move new sql server, config file needs changed new server details.

i have been told sql server 2000 can't migrate directly. should first go sql server 2008 , sql server 2012. please correct if not right understanding?

my problem around implementation plan task in production. can't move users in 1 go means migrating 100 users first , few other hundreds , left. means users might start using sql server 2012 while other still working sql server 2000. reason don't want in 1 go because it's risky in case of glitch , because application has 24x7 it's not possible bring down applications , update config files on each user's desktop.

but if allow 2000 , 2012 running (say 1 week until users move), make these databases out of sync , don't think can merged later because both databases may having same primary keys assigned different data.

i can't bring application down , take 4 hours outage allow users move new databases in 1 shot because application has 24x7.

can 1 recommend approach companies take migrate sql server without outage stated above keeping data consistency?

the easiest way handle create new 2012 instance , create database restore of 2000 database. have replication between 2 databases changes in either database published other way primary keys stay in sync. have down short period backup , restore move data assuming 2 servers co-located should matter of minutes. once users have been migrated turn off 2000 server.


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