Dell Perc H200A

[Vincent Hoffman]

On 10/09/2012 15:39, Paul Schmehl wrote:
> --On September 10, 2012 11:52:48 AM +0100 Vincent Hoffman
> <vince at unsane.co.uk> wrote:
>
>> If you are happy to use the integrated RAID (IR) mode and let the
>> driver/card handle RAID then
>> http://svnweb.freebsd.org/base?view=revision&revision=231679
>> brought in support for this and
>> http://svnweb.freebsd.org/base?view=revision&revision=237876
>> a new version of the driver.
>> A 9.1-RC1 install iso should pick it up fine.
>>
>
> Thanks, VIncent.  Does 8.3 also have the support?  Just wondering in
> case 9.1 RC1 is flaky on this particular box.

svnweb says yes
http://svnweb.freebsd.org/base/releng/8.3/sys/dev/mps/mps.c?view=log
>
>>
>> No idea if you want to use software RAID over JBOD (Just a bunch of
>> disks) mode though.
>>
>
> I would have thought hardware RAID would be better than software
> RAID.  No?
>
Hard to say here honestly. I've a few running as RAID under linux and
they seem to perform well enough. However I know some people prefer
using software RAID be it zfs or geom based RAID over hardware RAID.

LSI decribes the LSI 9211 its based on as " 6Gb/s SATA+SAS HBA with PCIe
2.0 host interface and basic RAID" (they come under HBA on LSI's website
not under RAID controllers.)
Dell's info says the h200 has no onboard cache or battery backup unit.
http://www.dell.com/content/topics/topic.aspx/global/products/pvaul/topics/en/us/raid_controller?c=us&l=en&cs=555
and that it disables the onboard cache on the drives (a good thing for
data integrity bad for performance)
http://support.dell.com/support/edocs/storage/Storlink/H200/en/UG/HTML/features.htm

So the gain here is only really offloading the minimal CPU used for RAID
management and that it gives you less admin overhead when changing disks
(hotswap and go vs manually adding into software RAID) in this case.




Vince