Question regarding Intel ICH7 motherboard and integrated RAID

[Howard Goldstein]

Maxim Khitrov wrote:
> On 9/16/07, Howard Goldstein <hg at queue.to> wrote:
>> There's a known issue with an interrupt storm when the ICH7R is
>> configured for AHCI or RAID, and a pr was filed back in July(don't have
>> the number, search for interrupt storm on atapci1+).  The suspicion was
>> that some peripheral no one has identified yet is hammering the apic and
>> we can't mask it.
...

> 
> Does this issue affect ICH9R as well? I'm about to get Gigabyte's
> GA-P35-DQ6 motherboard (also with Q6600) and was planning on
> configuring RAID10 array using the on-board ICH9R chipset. Are you
> saying that this doesn't current work (on 7-CURRENT), or that there
> are performance issues with such setup?

I don't know if it also affects the ICH9R or CURRENT or even on the
Gigabyte.  It definitely is a problem with the ICH7R and 6.2-STABLE on
an ASUS P5W DH.

Note that it actually does work but the performance hit is unbearable.
Whatever it is about AHCI mode causes about 37,000 interrupts per second
per vmstat -i, knocking the entire system performance down by about 50%
on a Q6600 pushed slightly (eg., 16 minutes to -j20 buildworld vs. 11
minutes to -j20 buildworld with IDE "compatibility" mode).

I don't believe you'll have any trouble with a geom managed RAID array
if your Gigabyte can support the IDE "compatibility" mode for the ICH9,
I'm using a variety of geom providers here simultaneously through the
ICH7R without any problem whatsoever in that mode.  The hit may not even
be noticeable since compatibility mode takes the interface down to
150MB/S SATA-I and common 7200RPM drives don't seem to be able to
sustain more than about 70 or 80MB/S.

> 
> I need to be able to dual-boot Win XP on the machine, so my plan was
> to get 4 320GB drives (later expanded to 6), put them into RAID10
> array and that way get good redundancy and performance in both
> operating systems. Would you suggest I go about doing this some other
> way?

I'd recommend two drives to the XP and your old motherboard, two to your
new system with the Q6600, resulting in an XP gaming and media system up
24/7 while you're getting your serious work and internet stuff done on
the CURRENT machine, but that's just me