Mixing SAS and SATA drives - working

Tue Mar 4 15:34:07 CST 2008

After some experiments i found following
original caddies with sata drives from Dell looks like this
http://www.mixx.org/dell/sata_red.jpg 
<http://www.mixx.org/dell/perc5front800x600.jpg>

IMHO that whole reduction is there to add these pins
http://www.mixx.org/dell/sata_pins.jpg 
<http://www.mixx.org/dell/perc5front800x600.jpg>
these pins are always on SAS drives connectors, but these are regular on 
SATA connectors, dell reduction add them also for SATA drives,
does enyone know what  are these for? is just for hotswap?

(i found some info on SUN 
http://docs.sun.com/source/820-0046-10/appc-pinouts.html it seems that 
these pins
have just Ground and no signal)

Weird thing is - when you connect to backplane SAS drives togehter with 
original caddies from dell (SATAu)with reduction
PERC6/i has problems as i described before

As i have spare caddies without reduction  (SATA) which i bought on Ebay 
for $15 for piece i conenct two Seagate 750GB spare drives
to them and found this interresting thing

*When you connect caddies with SAS together with caddies with SATA drive 
without this Dell reductions
as here http://www.mixx.org/dell/sata_no_red.jpg 
<http://www.mixx.org/dell/perc5front800x600.jpg> everything works 
without any problem :)*

Does anyone has an explanation?

Drives was connected as twice RAID1 - one for SAS and one for SATA 
drives, tried on PE 2950 with PERC6/i controller

R.H.
<http://www.mixx.org/dell/perc5front800x600.jpg>

Radim Hejc(
IT infrastructure
U-TURN, a.s.
Argentinská 38/286
17000 Praha 7, Czech rep.

Tony Molloy napsal(a):
> On Tuesday 04 March 2008 16:35:33 Radim Hejc wrote:
>   
>> I was trying today to mix two 76GB SAS 15krpm Fujitsu drives and two
>> 750GB Seagate SATA drives together
>> (2x RAID1 both Dell Originals) on PE 2950, but after server reboot i'm
>> still getting messages about Foreign configuration
>> from PERC/6i controller, then one of SATA drives is always degraded.
>> When i removed SAS everything seems to work fine
>>
>> strange thing, i will research more
>>
>>     
>
> That's interesting. That suggests that you can't mix them on the same 
> controller even if they are separate RAID arrays. I'll be interested to hear 
> what you come up with.
>
> In the end I could always go with all SATA drives. It would be cheaper ;-)
>
> Tony
>
>   
>> Radim Hejc(
>> IT infrastructure
>> U-TURN, a.s.
>> Argentinská 38/286
>> 17000 Praha 7, Czech rep.
>>
>> Tel.: +420.777190160
>> ICQ: 11064792
>>
>> Tony Molloy napsal(a):
>>     
>>> On Tuesday 04 March 2008 11:11:56 Mark Watts wrote:
>>>       
>>>> On Tuesday 04 March 2008 10:51:12 Tony Molloy wrote:
>>>>         
>>>>> On Tuesday 04 March 2008 09:49:37 Hostmaster wrote:
>>>>>           
>>>>>>>>> Can't mix SATA and SAS disks. So we can't supply 2X73GB, SAS,
>>>>>>>>> 3.5-inch, 15.000 rpm Hard Drive 4X750GB, SATA, 3.5-inch, 7200 rpm
>>>>>>>>> Hard Drive. Instead I've configured 2X73GB, SAS, 3.5-inch, 15.000
>>>>>>>>> rpm Hard Drive 4X400GB, SAS, 3.5-inch, 10,000 rpm Hard Drive.
>>>>>>>>>                   
>>>>>>> Can I do this and if I can how do I get Dell to supply me with that
>>>>>>> configuration.
>>>>>>>               
>>>>>> AFAIK its *technically* possible to mix them, however it isn't a Dell
>>>>>> supported configuration, therefore they won't sell them that way.
>>>>>> Several of the guys from Enterprise Storage frequent these lists, so
>>>>>> they will be able to give you the final word, but it might just be
>>>>>> easier to buy the server with the supported config (ie just the two
>>>>>> SAS drives for the OS), and then put a separate order for the four
>>>>>> SATA drives, but check with someone who knows the PERC6/i better than
>>>>>> me before buying!
>>>>>>             
>>>> This question has been asked before.
>>>>         
>>> As I said in my mail I know it has been asked before but I'm just about
>>> to spend 50,000+ euros on a rack so I wanted to be sure.
>>>
>>>       
>>>> You can mix SATA/SAS disks on the same backplane, but the cannot be in
>>>> the same logical volume.
>>>>         
>>> That was my impression of the previous thread so my RAID1/RAID5
>>> configuration should work. The problem then is to get Dell to sell that
>>> configuration to me.
>>>
>>> Thanks,
>>>
>>> Tony
>>>
>>>       
>>>> http://lists.us.dell.com/pipermail/linux-poweredge/2008-February/035159.
>>>> htm l
>>>>         
>>> _______________________________________________
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>>>       
>
>
>
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