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> note that in apache, your "listen" directives may not always be in
sync
> with, for example, your "virtualhost" lines, depending on your setup.
i
> foolishly spent too much figuring out that error once myself. there's
a
> thread in the lvs archive about it, take a look at:
>
http://marc.theaimsgroup.com/?l=linux-virtual-server&m=97613293904400&w=
2
Thanks for the heads up on this. I'll watch out for that when I'm
setting it all up.
> the problem with balancing something like pop3 is that you'd want both
of
> the real servers to have all the mail messages accessable for the
clients.
> also, when a client, say, deletes a message in his pop3 mailbox, that
> deletion needs to carry across to both/all of your real servers. if
> you're using something like nfs so that both of your real servers are
> accessing the same data, then you're set (well, maybe. if the pop3
> applications are nfs-safe, you're probably set. if not...). if not,
> things are going to be difficult keeping real server 1's data in sync
with
> real server 2's data.
What if I use some filesystem syncing software to copy changes to the
other machine? Like rsync? Does rsync go both ways or is it a
master-slave type of thing?
> sorry i couldn't give more specific help. if you're looking for more
info
> from the list, give some more details about the nature of your needs
and
> wants and how the backend applications should be functioning and all
that
> jazz and i'm sure you'll get some opinions and, oh yes, even more
options
> in response.
Thanks for your help. You've confused me a bit more as to the
differences between DR, NAT, and TUN, but you've also opened my eyes as
to what kinds of configurations are possible. I have a ton of
possibilities with the different configs. I didn't realize though that
with Direct Routing the real servers needed to be public. I thought when
the docs said that it needed to be on the same physical segment that it
meant it just needed to be connected with a switch and that it could all
be private. So does this mean that if I use DR that I won't need a
private hub/switch to connect the virtual server to the real servers?
Even if I don't need the second network adapters and the hub/switch,
I'll probably still want to use them as I assume it will speed up the
network when I'm doing things between real servers (such as rsync and
mysql replication).
I think overall I'm not going to be able to go much further without
having the actual servers to play with. The problem is that if I buy 3
cheap servers instead of 1 expensive one, then I'm pretty much
committing to do LVS even though I've never tried it. However, I'm
pretty close to certain that I'll be able to get it to work somehow,
even if it takes me a week to get everything running.
Thanks again for you help.
- Doug
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