[Gluster-users] Problem: Gluster performance too high..

[Jeff Darcy]

On 03/29/2012 03:30 PM, Harry Mangalam wrote:
> I'm doing some perf tests on a small gluster filesystem - 5 bricks on 4
> servers, all single-homed on the private net.
> 
> I've spawned up to 70 simultaneous jobs on our cluster nodes writing files of
> various sizes from /dev/zero to the gluster fs to see what the effect on the
> aggregate bandwith and the data is slightly unbelievable in that it seems to
> exceed the theoretical max of the network. (I used /dev/zero instead of
> /dev/urandom since /dev/urandom couldn't generate data fast enough.
> 
> The 35,000 files of the right size do hit the filesystem (of course they're all
> zero's) but the speed at which they transfer exceeds (by quite a bit) the
> theoretical max of a 1 Gb network.
> 
> Does gluster (or anything else) do transparent compression? What else would
> explain this oddity?

How do you define "theoretical max of a 1Gb network"?  If it's a switched
network, the actual maximum throughput depends on the capabilities of the
switch but is likely to be far in excess of 1Gb/s.  Could that be it?  Could
you give more detail about the actual traffic patterns and results?

BTW, this is my favorite message title ever.  Thanks for that.  :)