On 19 Jun 2011, at 16:54, Shanison wrote:
> Hi all,
>
> I have one Radiant website but deployed to a few servers, and one of
> the server S1 will be used to serve static file content and serve as a
> reverse proxy and redirect dynamic page request back to the other
> servers S2, S3, S4. So my question is that when admin login to the
> admin page, it can be from any of the servers, S2 or S3, S4. If he
> uploads files e.g. images to S2, how can the rest of servers serves
> the files? If a request comes in to display a page and is served at
> S3, that images used in the page won't be displayed as it is not in
> the same server.
>
> Is there a way to synchronize it? Thank you.
I've done this different ways in the past and the I think the right one would
depend on your reason for spreading across several servers in the first place:
* If it's for load-sharing, and you can think of one of the servers as the
master, you may find it's enough just to redirect all requests for /admin and
/assets to the master.
* if it's for redundancy and failover, you will need some scripting behind
radiant to move files around. Again, the method depends on your situation: you
can do it with rsync or an active push from the receiving server. It would be
easy to write an extension that triggered the mirroring script upon image
update, but note that you'd have to duplicate all the thumbnail sizes as well
as the original image.
* If it's geographical, or the other two solutions don't appeal, you could just
use a CDN with uplift, or the built-in S3 support we get from paperclip.
I think the most successful strategy I've used was to set up both database
servers (this was a rather paranoid and very busy site) as simple static-file
asset servers, and to direct all requests for static files from those two.
There were some rather basic rsync scripts to mirror uploaded assets. I figured
that if the database went down then the rest didn't really matter anyway.
If anyone knows a standard (cross-platform) way that we could meet this
requirement from within radiant's asset manager I'd be very happy to write it
in.
For what it's worth, I don't deploy across multiple servers any more, apart
from a separate database host. More recently I've found that one decent server
with a long cache life is more efficient than several with only brief caches
(as they must be, because you're only ever clearing the cache on one of them).
best,
will