Re: Software vs. Hardware RAID Data

On Tue, Aug 19, 2008 at 10:49 PM,  <david@lang.hm> wrote:
> On Tue, 19 Aug 2008, Mark Wong wrote:
>
>> Hi all,
>>
>> We started an attempt to slice the data we've been collecting in
>> another way, to show the results of software vs. hardware RAID:
>>
>>
>> http://wiki.postgresql.org/wiki/HP_ProLiant_DL380_G5_Tuning_Guide#Hardware_vs._Software_Raid
>>
>> The angle we're trying to show here is the processor utilization and
>> i/o throughput for a given file system and raid configuration.  I
>> wasn't sure about the best way to present it, so this is how it looks
>> so far.  Click on the results for a chart of the aggregate processor
>> utilization for the test.
>>
>> Comments, suggestions, criticisms, et al. welcome.
>
> it's really good to show cpu utilization as well as throughput, but how
> about showing the cpu utilization as %cpu per MB/s (possibly with a flag to
> indicate any entries that look like they may have hit cpu limits)

Ok, we'll add that and see how it looks.

> why did you use 4M stripe size on the software raid? especially on raid 5
> this seems like a lot of data to have to touch when making an update.

I'm sort of taking a shotgun approach, but ultimately we hope to show
whether there is significant impact of the stripe width relative to
the database blocksize.

Regards,
Mark