Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
So I've got a couple of webservers which mirror each other without the use of a fileserver backend. Up until now they've been using csync2 to mirror the data between the servers and it has been working fairly well (and the built-in file backup has come in handy once or twice as well). Unfortunately csync2 has a good deal of limitations as well, such as the more files you have, the slower it is, and you can't sync more than one server to other servers (in this case only one) at the same time. I'm running it in a master/master mode. Overall it was designed to be more of a tool to update configs, or update relatively non-interactive systems. So recently I've been looking more and more at DRBD and NFS (before I spend a couple of grand on a well built fileserver). So what I am looking at is something like this: server A (DRBD + active NFS) + mounted by itself and server B server B (DRBD + disabled NFS) + mounts server A NFS share So while server A is the active NFS server and server B is passive and only synching, both servers would mount via NFS server A. When server A goes down for whatever reason (reboot, crash, etc) server B will take over and continue where server A left off. One thing I keep seeing in various documents however is a warning not to have the server mount its own NFS shares. There is never reason (even a vague reason) given why not to however. I can see the obvious reasons (eg. infinitely nested filesystems via symlinks/mounts, crossmounts, etc), but my directory structures should not need anything like this at all. Other than overall system complexity, I don't see any reasons to not be able to self mount NFS with a whole lot of trouble. The problems I see include Apache log files (I'd assume each server would have to write to separate logs), and what happens when the servers disconnect from each other (eg. NIC failure) but are both still active and both decide they are masters. How are synchronization issues then resolved? __________________________________________________________ Dan Brown danb at zu.com