I/O modes

Global Active Device for VSP One Block
Version
10.5.x
File Size
25537 KB
Audience
anonymous
Part Number
MK-23VSP1B011-11
ft:lastEdition
2026-06-23

You should understand the I/O actions on the P-VOL and the S-VOL of a GAD pair.

The following table lists and describes the GAD I/O modes.

I/O mode CCI1 Read processing Write processing
Mirror (RL) L/M Sends data from the storage system that received a read request to the server. Writes data to the P-VOL and then the S-VOL.
Local L/L Sends data from the storage system that received a read request to the server. Writes data to the volume on the storage system that received a write request.
Block2 B/B Rejected (Replies to illegal requests). Rejected (Replies to illegal requests).

Notes:

  1. In CCI, the I/O mode is displayed as <read processing>/<write processing> in which L indicates Local, M indicates Mirror, and B indicates Block (for example, L/L indicates Local read processing and Local write processing).
  2. For volumes whose I/O mode is Block, a response indicating that the LU is undefined is returned to the Report LUN and Inquiry commands. Therefore, servers cannot identify a volume whose I/O mode is Block, or the path of this volume is blocked.