R740xd dual PERC controllers configuration

Jancipra,

The disks are controlled as shown on page 261 here, which you can see below.

Split mode — One controller has access to the first 12 drives and the second controller has access to the last 12 drives. The drives connected to the first controller are numbered 0-11 while the drives connected to the second controller are numbered 12-23.

Split mode 4:20 — One controller has access to the first 4 drives and the second controller has access to the last 20 drives. The drives connected to the first controller are numbered 0-3 while the drives connected to the second controller are numbered 4-23.

Split mode 8:16 — One controller has access to the first 8 drives and the second controller has access to the last 16 drives. The drives connected to the first controller are numbered 0-7 while the drives connected to the second controller are numbered 8-23.

Split mode 16:8 — One controller has access to the first 16 drives and the second controller has access to the last 8 drives. The drives connected to the first controller are numbered 0-15 while the drives connected to the second controller are numbered 16-23.

Split mode 20:4 — One controller has access to the first 20 drives and the second controller has access to the last 4 drives. The drives connected to the first controller are numbered 0-19 while the drives connected to the second controller are numbered 20-23.

Let me know if this answers your question, or if you have any other questions or concerns.

Chris,

One thing not mentioned in your reply was the default unifed mode. If the system has dual controllers in unified mode, what happens when the primary controller fails? Will the secondary controller take over and continue operations? If so, is there any downtime during the failover?

Hello there, does anyone has an answer to @BSmith-MMO's question ? I'm also wondering how is it handled (for my T630)

Hello,
for this question
"If the system has dual controllers in unified mode, what happens when the primary controller fails? Will the secondary controller take over" 
The answer is a no.

What your talking here is "redundant" and it's possible only in VRTX. I'm afraid.