xp512 array groups

[James Hicks]

My customer has an xp512 with one DKU
We're going to configure 2 hotspares at 48GB and 73GB.

What is the number of array groups I can have.

Thanks in advance

[Dave Wherry · Accepted solution]

I have not been able to find this information. I can tell you about the XP256 though.
One DKU holds 64 disks, or 16 disk groups. Once you add a hot spare that takes up one of the disk groups. You can mix different size spares in that "group" You will use 2 of the 4 drive bays in that group, leaving 2 for other spares.
This leaves you 15 drive bays, or cannisters (cans) for data disks.
The XP256 goes up to 256 disks by using 4 DKU's - 4 * 64. The XP512 can have 512 disks. I'm not sure if they do that by doubling the number of DKU's or increasing the number of disks that can go in a DKU.
If your customer already has the XP on-site simply open the door and count the cans. Then divide by 4.

[Dave Wherry]

James,
I got some more information today. The XP512 can have up to 96 disks in a DKU. They are putting a larger number of smaller form factor drives in the same size cabinet. You should be able to get up to 24 disk arrays in a single cabinet.
They have also added 2 more cabinets to the configuration for a total of 6. That's a total of 576 disks. You lose capacity though when you add hot spares.

[Vincent Fleming]

Actually, the R1 DKU (first right side disk cabinet) can hold 23 array groups, as one of the array group slots is reserved for spares.

The R2 (second right side cabinet) can hold 24 array groups, as can L1 and L2 (the first two left side cabinets).

The R3 and L3 cabinets (3rd cabinets on the left and right) hold 64 drives instead of the 96 that the R1, R2, L1, L2 cabinet hold. This makes for 16 array groups.

So, R1, R2, L1, L2 at 96 disks + R3, L3 at 64 disks = a total of 512 drives, including spares.

[Peter Mattei]

As Vincent explained, there can be up to 512 disk mechs in a XP512. See the attached drawing I made for clarification.
8 drives are exclusively reserved for hot spares (the yellow ones). So 504 drives can be used for operation.
I you want more spares, you can have up to 16 total, taking 8 off the operational ones.

Regards
Peter