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Two Smart Array connected to single HDD backplane

Frequent Advisor

Two Smart Array connected to single HDD backplane

HW profile:

We have a server (DL360p Gen8 - 10x SFF model). One port of HDD backlane is connected to internal P420i/1G controller. Second port from HDD backplane is connected to P822/2G controller. All 10 HDDs are installed. Both controllers can see all 10 disks as unassigned.



From ACU (before installing any OS) we create RAID-1 array on 2 HDDs from P420i controller and RAID-5 on 3 HDDs from P822 controller. So P420i can see RAID-1 and 8 unassigned HDDs, while P822 can see RAID-5 and 7 unassigned HDDs.


After server reboot the both controlers can see the same picture: RAID-1 , RAID-5 and 5 unassigned HDDs.




1/ How can I verify to which controller belongs each array (RAID-1 and RAID-5)?

2/ How can I force one controller to serve one array (RAID-1) and other controller to serve second array (RAID-5)?




P.S. This thread has been moevd from Servers > General to ProLiant Servers (ML,DL,SL). - HP Forum Moderator

Valued Contributor

Re: Two Smart Array connected to single HDD backplane

what you have there is multiple active paths. with ESXi this is a good thing for redunancy and load balancing.


HPACUCLI has SSP zoning where you tell each raid card which drives to see similar to FC zoning. I am not sure how to do this with the GUI but ACUCLI it's pretty straight forward.


I am not sure you can zone logical lun's , usually its done per drive.


However if you are using a cluster filesystem (CSV,VMFS) for virtualization, it's not a problem since both controllers can actively dish out commands to all of the drives without corruption. This is an internal cluster.


An external cluster might be a MDS6000 with two computers and 2 to 4 raid controllers and 70 hard drives. The older MDS600 goes for like $599 used on ebay!! 70 drive slots!! wow.


Otherwise you have to get into zoning using  a sas switch, which are external mostly.


It is a very cool feature not many people know about!


Don't forget to buy HP SAAP 2.0 for P420 to enable HP SmartCache! I've used an old X25-M 160gb ssd (1) in front of 7 450GB SAS drives and had tremendous random i/o benefits from SSD caching. I repeatedly pulled the drive while doing a heavy read/write benchmark with verify and the system never corrupted a bit! Awesome feature! Comes with SAAP 2.0 and you can do 1.5TB with 2gb FBWC or 750GB with 1gb FBWC of ssd cache. 


Say you had 1TB of SSD you could do 750gb of caching to a raid volume, or 250/500 to two, and then raid-1 stripe the rest of the 1TB (250gb -> raid 1 125gb) and boot windows server or esxi off that!


I use all of these features on my DL180 G6, DL380 G7, DL360 G6 - you say the P420/1gb FBWC is not compatible? wrong. It runs too hot and does a thermal shutdown. Nothing some arctic silver and proper placement of the card in a well flowing slot can't fix!! 


The P420 will overheat in Gen8 machines too! 


BTW the SMARTCACHE feature doesn't care if you use non-hp drives, nor does it check authenticity in G6 or G7 machines since you don't have smart-carriers!


Why did I bother? Well folks were selling legit new P420/1gb FBWC for $249 and that was  smarter than buying new batteries for my old Lefthand P4300 G2 units! Supercaps give you 10 years of service, plus HP SAAP 2.0 SMARTCACHE is licensed per box. So you can have 4 raid controllers and pay once for the key legally! (unlike LSI, i'm looking at you!!)