On Tue, 16 Jun 2009 18:58:56 +0600 Mike Kazantsev <mk.frag...@gmail.com> wrote:
> On Tue, 16 Jun 2009 12:40:46 +0200 > Renat Golubchyk <ragerm...@gmx.net> wrote: > > > Hi all! > > > > Short: > > What is the best way to setup something similar to RAID 1 over a > > WAN? > > ... > > > One purpose of the setup is to have data redundancy. Thus we have to > > ensure that the data is replicated in a timely manner. Replicating > > MySQL data is not difficult. The problem is the file system data > > like uploaded documents and pictures. We can monitor changes in the > > file system and initiate rsync to copy files over the network, but > > I think it's not a good solution. What we are after is a network > > equivalent of RAID 1. Are there any viable solutions that could > > work over a WAN? > > If replication after file is completely hit the disk is not acceptable > either because files are quite large or have to be really synchronous > then I'll second DRBD-with-HA-cluster-fs suggestion. > DRBD is HA solution which is achieved by switching the role of the nodes in case the "active node" goes offline. I think DRBD is not meant for the schema OP has described, because only the "active node" is accessible via FS. DRBD works between the FS and block device layers. It catches the FS writes from the active node and sends them over the network. DRBD on the backup node receives those and replicates them directly to the disk driver. Thus you can't have mounted FS on the backup node. If the active node goes offline, the backup node takes over which means DRBD switches roles and the FS has to be mounted afterwards. -- Best regards, Daniel
