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P400 - seperate channels?

 
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Jesse Rink
Advisor

P400 - seperate channels?

If I want to setup a RAID-1 array, and a RAID-5 array on the same P400 controller, a) Can I have them on seperate channels? If so, how? and b) Will performance be increased by having them on seperate channels instead of sharing the same channel?

Thanks
5 REPLIES
Marek Nelec
Honored Contributor
Solution

Re: P400 - seperate channels?

Unless you are using this P400 in a server other than ML570 G4, every SAS/SATA drive has dedicated channel to the controller. That's one of the differences between SAS and SCSI.
Mauro Rusignuolo
Trusted Contributor

Re: P400 - seperate channels?

... also... is recommended don't mix SATA and SAS HDs on the same array.
performance will decrease consistently.
it's possible to mix HDs but non suggested.

(Marek ... don't hate me ... :-) )

TJK
<> Leonardo da Vinci
Jesse Rink
Advisor

Re: P400 - seperate channels?

I never knew that SAS drives each had their own channel. Thanks for the tip.
Marek Nelec
Honored Contributor

Re: P400 - seperate channels?

To be clear - it depends on a cage drive type, or enclosure. P400 has 2 4-lane SAS connectors, so if it is connected to a 6-drive SAS cage, or 8-drive SAS cage, every SAS/SATA drive has dedicated channel to a controller. Things are different if it's ML570 G4, which has 18-drive cage. P400 supports up to 18 drives, but the backplane of the drive cage is different, so it can connect 18 drives to 8 SAS lanes. SA-P800, for example has 2 4-lane external connectors, and you can connect up to to 100 2.5 SAS drives using 4 MSA70 enclosures, but these 8 SAS channels will be of course shared by all these drives.
Mauro Rusignuolo
Trusted Contributor

Re: P400 - seperate channels?

does't depends on the cage drive tipe or enclosure.
depends on the controller you have and on the number of HD you want to connect.
if the number of channel of the controller are less than the number of HD you want to connect, you need not only the controller and "back-plane" (that is not the same thing intended for the SCSI), but, also, fan-out and/or edge.
so, you can connect, independently of the number of the port (or channel) of your controller, up to 16'256 mixed SAS/SATA drive.

TJK
<> Leonardo da Vinci