[drupal-support] Multiple HTTP Servers, one database?

[vlado]

On Sun, 2005-10-09 at 11:43 +0200, Dries Buytaert wrote:
> On 06 Oct 2005, at 15:45, Adam Gaffin wrote:
> > We're running Drupal in a server farm. The only thing we had to do
> > differently was to make sure that the config file pointed at the  
> > database
> > server, rather than localhost. I make changes to files (style sheets,
> > templates, settings.php, etc.) on our master server, which then  
> > replicates
> > everything out to the other servers. All of this is behind some
> > fancy-shmancy load balancer (Alteon, I think); the only problems  
> > we've ever
> > had is when one of the servers goes kablooey and stops accepting  
> > updated
> > files for one reason or another, and that's hardly Drupal's fault!
> 
> Just wondering; how do you deal with users uploading documents (eg.  
> avatars/pictures)?  Do you put these on an NFS share so they become  
> instantly visible on all servers?  We're considering to leverage  
> Apache's proxy passthrough for this, rather than using an NFS share.

I was trying these and a few other solutions, and it really depends on
you hardware and software setup and degree of control.

* NFS has a problem with locks - locking is not guaranteed or is
relatively slow.
* passthrough will work, but for files you will end up with only one
backend - might be allright, depends on the case
* a cluster file system - gfs, cnfs, .... will do it out of the box, but
requires more complicated setup and maintenance
* scripts + cvs/svn/other version control system - there is a lag in
the file updates, but otherwise works fine, except for rare race
conditions, like file uploaded a couple of times to different web
servers, before it was synced