[Linux-cluster] WebFarm using RedHat cluster suite ?

[Lon Hohberger]

On Wed, 2006-01-18 at 15:33 -0500, FM wrote:
> Hello everybody,
> 
> Is redhat cluster suite (RHEL 4 ) a good candidate for a webfarm ?
> My setup would be : several servers (1U AMd dual core) connected to 
> iscsi storage array.

Is this your expected configuration?

 server     server     server
   |          |          |
   +----------+----------+     <-- cool gigabit ethernet backbone
              |
             GFS
              |
iSCSI target doing RAID internally
              |
            disks

You can also do the following to avoid GFS, if your NAS has iSCSI target
has NFS capabilities:

 server     server     server
   |          |          |
   +----------+----------+     <-- cool gigabit ethernet backbone
              |
    NFS Appliance/Server
              |
            disks

Or, if the data doesn't change often:

 server     server     server
   ^          ^          ^
   +-<-<-<-<--+-->->->->-+     <-- cool gigabit ethernet backbone
              ^
              ^                <-- one-way, periodic 'push'
            server                 of static content.  Web servers 
              |                    can not write to the main server
            disks

On the front-end, you can use piranha + LVS to balance traffic between
the web servers.  Do *not* do the following, as the servers' caches/RAID
metadata will not necessarily be in sync with each other:

 server     server     server
   |          |          |
md RAID    md RAID    md RAID
   |          |          |
   +----+-----+-----+----+
        |           |
   iSCSI disk  iSCSI disk
	
-- Lon