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

[Jeff White]

Maybe it's cheating by writing sparse files or something of the like 
because it knows it's all zeros?  Create some files locally from 
/dev/urandom and copy them.  I think you'll see much lower performance.  
Better yet, use bonnie++.

Jeff White - Linux/Unix Systems Engineer
University of Pittsburgh - CSSD


On 03/29/2012 03:34 PM, Jeff Darcy wrote:
> 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.  :)
>
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