[Linux-cluster] GFS or Web Server Performance issues?

[Wendy Cheng]

gordan at bobich.net wrote:
> I think a part of the problem is perception. Clustering in most cases 
> leads to _LOWER_ performance on I/O bound processes. If it's CPU 
> bound, then sure, it'll help. But on I/O it'll likely do you harm. 
> It's more about redundancy and graceful degradation than performance. 
> There's no way of getting away from the fact that a cluster has to do 
> more work than a single node, just because it has to keep itself in sync.
>
> The only way clustering will give you scaleable performance benefit is 
> with partitioned (as opposed to shared) data. Shared data clustering 
> is about convenience and redundancy, not about performance.
>
Well said ! This reminds me some of previous conversations with 
customers in mid-90 when people started to port their applications from 
supercomputers and/or big SMP boxes into clustered machines. It had 
taken non-trivial amount of collaborative efforts between the customers 
and the team's application enablement group to achieve the expected 
performance when moving applications between different platforms. Be 
aware that cluster management and its associated performance tuning is 
really not a trivial task. It is kind of hard to give a "catch-all" 
advice in a mailing list, particularly we have been participating the 
discussions on our spare time basis.

-- Wendy