[lvs-users] How can I improve LVS performance?

Graeme Fowler graeme at graemef.net
Thu Aug 6 00:11:06 BST 2009

On Wed, 2009-08-05 at 23:49 +0100, Paulo Rodrigues wrote:
> I'll have to change the network around to be able to do this, perhaps over
> the weekend.

Given your following comments, you may not have to - but it will give
you a decent baseline for "idealised" operation.

Unfortunately, once you have remote clients accessing a system then you
have all the variations they can throw at you - PMTU problems,
non-deterministic latency changes, TCP window scaling... etc etc. The
list can grow very long, and tiresome!

If you figure out that you can handle (say) 1000 page views/second in
tests, you might find that in a "real" operating environment you manage
to achieve 25% of that. At least, if you do, you'll know you are doing

Remember also that static tests of the type you did don't exactly stress
the system as it can deliver a lot of data from the kernel's filesystem
cache (in memory) rather than reading from disk. If you can do so,
modify your PHP to do some sort of calculation or fetch some data in a
random fashion from your database (as MySQL will also cache repeated
requests if configured appropriately).

Not that any of that is LVS related, of course; it's just good practice
when establishing a baseline for your system :)

Glad we've helped so far!


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