> Hi list ! > > I am currently deploying two servers (Windows 2003 R2) that will be > used as file servers as well as PostgreSQL servers. > > One of the server will be the main server, the other one a backup > server (no load-balancing, only an easy-recoverage solution). > The goal is to be able to start working quickly after one of the > server fails (after the main server fails actually, since the > backup server is not used). > > I already configured a high-availability solution for the file > server part by using the built-in DFS Replication service. > > I first thought I would use Slony-I to replicate changes to the > main database on the backup server, but I then realized that I > might use DFS Replication for that. > The point is that I am not sure that it will work. > > Documentation about DFS Replication is not very talkative (IMHO), I > have to little knowledge of PostgreSQL's file handling to know if > it will work or not. > > I have compiled some informations about DFS Replication from > Microsoft"s web site. Could you PostgreSQL gurus tell me whether > using this replication mechanism is a good idea or not ? > The main advantage for me is that I will not need to configure 2 > replication systems (one for the files, on for the DBs). I would > only need to maintain one of them ! To add to this thread, even if it's a bit late: It is *not* safe to use DFS/FRS replication for your PostgreSQL data directory. DFS is not synchronous (which means you could lose committed data or parts thereof), and it does *not* guarantee write order (which means your database will quite likely end up completely corrupt if you get a failover whenever anything is happening). > * DFS Replication detects changes on the volume by monitoring the > update sequence number (USN) journal, and DFS Replication > replicates changes only after the file is closed. This is also a problem - PostgreSQL generally doesn't close its files until it's really necessary. //Magnus
