more comments...

On May 1, 2012, at 10:41 AM, Ray Van Dolson wrote:

> On Tue, May 01, 2012 at 07:18:18AM -0700, Bob Friesenhahn wrote:
>> On Mon, 30 Apr 2012, Ray Van Dolson wrote:
>>> I'm trying to run some IOzone benchmarking on a new system to get a
>>> feel for baseline performance.
>> Unfortunately, benchmarking with IOzone is a very poor indicator of 
>> what performance will be like during normal use.  Forcing the system 
>> to behave like it is short on memory only tests how the system will 
>> behave when it is short on memory.
>> Testing multi-threaded synchronous writes with IOzone might actually 
>> mean something if it is representative of your work-load.
>> Bob
> Sounds like IOzone may not be my best option here (though it does
> produce pretty graphs).

For performance analysis of ZFS systems, you need to consider the advantages
of the hybrid storage pool. I wrote a white paper last summer describing a model
that you can use with your performance measurements or data from vendor 

And in presentation form,

Recently, this model has been expanded and enhanced. Contact me offline, if you
are interested.

I have used IOzone, filebench, and vdbench for a lot of performance 
lately. Each has their own strength, but all can build a full characterization 
profile of a

For IOzone, I like to run a full characterization run, which precludes 
multithreaded runs,
for a spectrum of I/O sizes and WSS. Such info can be useful to explore the 
of your system's performance and compare to other systems. 

Also, for systems with > 50GB of RAM, there are some tunables needed for good 
under heavy write load workloads. Alas, there is no perfect answer and no 
single tunable
setting works optimally for all cases. WIP. YMMV.

A single, summary metric is not very useful...

> bonnie++ actually gave me more realistic sounding numbers, and I've
> been reading good thigns about fio.

IMNSHO, bonnie++ is a totally useless benchmark. Roch disected it rather nicely 

[gag me!  Does Oracle have butugly URLs or what? ;-)]
 -- richard

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