• DKC - Disk controller, can also hold 128 drives in a USP-V
  • DKU - Disk expansion unit, holds 256 drives in a USP-V
  • CHA - Channel adapters, cache to host, contain host ports
  • DKA - Disk adapters, cache to disk, connec to back end drives
  • CSW - Cache switch, controls movement from cache to hosts and drives

This can be represented as follows:


CSW + 1D/2P controls CHA0+1 and DKA0+1. If additional CHAs/DKAs are added, an additional CSW is required at 1J/2V

The USP-V is split into Cluster 1 (front) and Cluster 2 (back). These contain 16 or 8 port CHAs. The port numbers are as follows:

1A 3A 1E 3E 2A 4A
5A 7A 5E 7E 6A 8A
1B 3B etc etc
5B 7B
1C 3C
5C 7C
1D 3D
5D 7D
(odd numbers)(even numbers)

A 16 port CHA has 8 processors, CHP00 controls 1A & 5A, CHP01 3A & 7A, etc

Queue depths

1024 queued commands per port 512
32 queued commands per LUN 32

So if a SCSI queue depth on a server (sd_max_throttle on Solaris) is set to 32, the maximum recommended LUNs per port will be 32 (32 x 32 = 1024)

Recent Changes

Contribute to this wiki

Why not help others by sharing your knowledge? Contribute something to this wiki and join out hall of fame!
Contact us for a user name and password