If my 3PAR has 3 x cages, does that mean that I have to create my CPGs with 3 "disks"?

[StuartA46]

On our old P10000 V400 we had disks in 4 x cages.  So we created the disks so that the CPGs were 3+1.  Now we only have 3 cages on the 7200, so do the CPGs have to be 2+1?  Is that how that works?  They call that "cage availability", I think.

Is there a manual that specifically explains this?

   Stuart

P.S. This thread has been moved from  Storage > General   to Storage Area Networks (SAN) (Enterprise). -HP forum moderator

[Dennis Handly]

>so do the CPGs have to be 2+1?

Yes, if you want HA cage.  RAID 1 would also work.

>Is there a manual that specifically explains this?

Have you looked at the Concepts Guide?

http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual&lang=en&cc=us&docIndexId=64179&taskId=101&prodTypeId=12169&prodSeriesId=5335712

http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c03606434/c03606434.pdf

System Guidelines for Creating CPGs

[StuartA46 · Accepted solution]

That's a good answer, then I had a thought:  We use RAID-6 for something and I think it has 4+2 in four cages.  So, how does that work?  does it take 4 chunklets based on cage availability then take 2 more chunklets from the next 2 x disk "row"?

[Dennis Handly]

>how does that work?  does it take 4 chunklets based on cage availability ...

How did you create the VV?  How did you create your CPG?

Given a VV:

showld -vv vv-name  # lists the LDs

showldch -lformat set -linfo pdid,pdch ld-name        # lists the chunklets in a LD

The default is 8 chunklets in a RAID 6 set.  And with HA cage, they alternate on the 4 cages.

[Sheldon Smith]

RAID6 takes two chunklets from each cage. 4D+2P would be across three cages.