LVS
lvs-users
Google
 
Web LinuxVirtualServer.org

Re: Possible to Load Balance NFS.

To: Jeff Langley <jlangley@xxxxxxxxxxxxx>
Subject: Re: Possible to Load Balance NFS.
Cc: "'lvs-users@xxxxxxxxxxxxxxxxxxxxxx'" <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
From: Paul Lussier <pll@xxxxxxxxxxx>
Date: Thu, 11 May 2000 11:52:11 -0400
In a message dated: Thu, 11 May 2000 10:30:04 EDT
Jeff Langley said:

>Hi Everyone,
>
>I am researching the possiblity to do load balancing of NFS both dynamic
>and direct type automounts.

The problem with load balancing NFS is that you then need to have more than 1 
system accessing the same physical drive (or RAID array), *or* have multiple 
copies of the data scattered among different machines.

With the latter scenario, you end up with an updating problem.  Typically, 
this type of configuration would only be used if the data being served were 
essentially static, which implies that it's not to be used for things like 
home directories, development areas, mail/print spools, etc.

If you are planning on using it this way, you can do some sort of load 
balancing with NFS/Automount natively.  For example, and automount map like:

   /static/stuff        systemA:/stuff,systemB:/otherstuff,systemC:/morestuff

would tell the client to mount /static/stuff from whichever system responded 
first, which would presumably be the machine with either the lightest load or 
fasted network connection.  Granted, it doesn't always work that way, and LVS 
may well be a better way to do this.

The former configuration though, where you need constantly changing dynamic 
data being shared is quite tricky.  2 systems must not only access the same 
drive/array/bus, but must also be simultaneously *changing* that data.  This 
isn't good, since neither has any idea of what the other is doing.  Making the 
systems aware of each other, I would guess would be more in the scop of a 
kernel development group, not the LVS/HA groups, but I might be wrong, being 
new to this group myself.

I would enjoy more discussion on this topic, as I'm not all that knowledgable 
on how one *could* load balance NFS among multiple systems.  Especially if 
there are ways around what I've already mentioned.

Thanks,

-- 
Seeya,
Paul
----
        "I always explain our company via interpretive dance.
             I meet lots of interesting people that way."
                                          Niall Kavanagh, 10 April, 2000

         If you're not having fun, you're not doing it right!




<Prev in Thread] Current Thread [Next in Thread>