Re: Best suiting OS

Scott Carey wrote:
> On 10/5/09 11:15 AM, "Karl Denninger" <karl(at)denninger(dot)net> wrote:
>
>
>> I'm running the 9650s in most of my "busier" machines. Haven't tried a
>> PERC card yet - its on my list. Most of my stuff is configured as RAID
>> 1 although I have a couple of RAID 10 arrays in service; depending on
>> the data set and how it splits up I prefer to have more control of how
>> I/O is partitioned rather than let the controller pick through striping.
>>
>> I don't think I have any of the 95xx stuff out in the wild at present;
>> it didn't do particularly well in my testing in terms of performance.
>>
>> -- Karl
>>
> Let me make sure I clarify here --
>
> The 3ware 9[56]xx issues I have seen were with throughput on larger RAID
> array sizes -- 8+ disks total. On smaller arrays, I have not tested.
>
>
Interesting... I'm curious if that's why I haven't run into it - I get
damn close to N x rotational on sequential I/O out of these boards; you
can't really do better than the physics allow :)

I'll have to play with some larger (> 8 unit) Raid 1 and Raid 10 arrays
and compare to see if there's a "knee" point and whether its a function
of the aggregation through the chipset or whether it's a card issue. I
suspect it's related to the aggregation as otherwise I'd have seen it on
some of my larger configurations, but I tend to run multiple adapters
for anything more than 8 spindles, which precludes the situation you've
seen.

Of course if you NEED 12 spindles in one logical device for capacity
reasons........

-- Karl