Re: [cobalt-users] Load Balancing Cobalts ?

["Dave" <nuzman@xxxxxxxxxx>]

Mirroring two RaQs seems to be an interesting challenge... especially for
mail... considering MX only happens on a single IP address. What if user
logs into server2 and mail is being delivered to server1?

Web/ftp is relatively simple to make work. Where I work, we use round-robin
in DNS to present hosts www1 and www2 as www and simply cron (or manually
run) a script to copy web root from www1 to www2. We're moving these to
multiple Win2k boxes and will use a NetScreen firewall to handle the load
balancing.

Another option for higher volume sites, point multiple systems back to a
common NFS mounted NAS volume. This way you only have one place to
store/edit data. Then you only have to provide some method of presenting the
multiple servers as a single address. This way your NAS is the point that
needs redundancy. I'm told Apache will scream when the server can simply
hand out pages without needing to handle disk reads.

Cheers!

Dave

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----- Original Message -----
From: "Rodolfo J. Paiz" <rpaiz@xxxxxxxxxxxxxx>
To: <cobalt-users@xxxxxxxxxxxxxxx>
Sent: Monday, April 09, 2001 8:57 AM
Subject: RE: [cobalt-users] Load Balancing Cobalts ?


> At 4/8/01 11:49 PM -0400, you wrote:
> > > If I intend to load-balance two cobalts, how do I ensure that
> > > data passed-in
> > > from users are written to both servers ? This is especially so when
users
> > > make changes to their emails, perform backups, administer their
> > > sites online
> > > and even FTP.
> > >
> >It sounds like you're talking about RAID, that I believe is available.
>
> Nah... RAID is for speed and/or fault-tolerance on disks within one
server.
> What this guy wants (and what I want) is more like failover, where you
have
> a standby machine that takes over instantly if the first fails, or
> clustering, where you have two machines that are essentially full mirrors
> of each other: they share the load (providing much more power) and if one
> fails the other keeps going.
>
> Obviously clustering is better, since it also allows you to add machines
so
> that eventually you have N servers providing both load-balancing and
> fault-tolerance.
>
> Cobalt provides a failover solution in its StaQware application. Of
course,
> then you only have failover, and no load-balancing so that's an expensive
> solution.
>
> >There have also been some mentions, although I haven't seen anyone say
> >they're using it, of rsync:
> >http://rsync.samba.org/rsync/features.html
>
> I'm now using rsync to mirror the Linux Documentation Project and to
create
> a mirror of the RedHat FTP site. Eventually (next 2-3 months) I'll be
using
> it to make a backup of my server; I'll post details then, but I can say
now
> that rsync is a very easy tool to use and comes highly recommended.
>
>
> --
> Rodolfo J. Paiz
> rpaiz@xxxxxxxxxxxxxx
>
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