Relationship Between Gad Status, Pair Status, And I/O Mode - Hitachi G1000 User Manual

I/O
mode
Mirror
(RL)
Local
2
Block
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.
Related topics
• Monitoring GAD status on page 1-10

Relationship between GAD status, pair status, and I/O mode

The following table lists the GAD statuses and describes the relationship
between the GAD status, pair status, and I/O mode. "N" indicates that pair
status or I/O mode cannot be identified due to a failure in the storage
system.
GAD
status
Simplex
Mirroring
Mirrored
Suspended Pair
Hitachi Virtual Storage Platform G1000 Global-Active Device User Guide
I/O mode
1
HCS
CCI
L/M Mirror Sends data from the
(Read storage system that
Local) received a read request to
the server.
L/L Local Sends data from the
storage system that
received a read request to
the server.
B/B Block Rejected (Replies to illegal
requests).
When to
Pair
suspend
status
Not SMPL
applicable
Not INIT
applicable
Not COPY
applicable
Not PAIR
applicable
PSUS
operation
Overview of global-active device
Read processing
P-VOL
Pair
I/O mode
status
Not SMPL
applicable
Mirror (RL) INIT
Mirror (RL) COPY
Mirror (RL) PAIR
Local SSUS
Write processing
Writes data to the P-VOL
and then the S-VOL.
Writes data to the volume
on the storage system
that received a write
request.
Rejected (Replies to illegal
requests).
S-VOL Volume
that has
the latest
I/O mode
data
Not Not
applicable applicable
Block P-VOL
Block P-VOL
Mirror (RL) P-VOL and
S-VOL
Block P-VOL
1-13