Hitachi G1000 - Global-active device and server I;O

GAD
status
When to
suspend
P-VOL S-VOL Volume
that has
the latest
data
Pair
status
I/O mode
Pair
status
I/O mode
Failure PSUE* Local PSUE Block P-VOL
PSUE* Local SMPL -- P-VOL
PSUE* Local N N P-VOL
Pair
operation
PSUS Block SSWS Local S-VOL
Failure PSUE Block SSWS* Local S-VOL
SMPL -- SSWS* Local S-VOL
N N SSWS* Local S-VOL
Blocked Not
applicable
PSUE Block PSUE Block P-VOL and
S-VOL
Not
applicable
PSUE Block N N P-VOL and
S-VOL
Not
applicable
N N PSUE Block P-VOL and
S-VOL
*If the server does not issue the write I/O, the pair status might be PAIR, depending on
the failure location.
Related topics
• Monitoring GAD status on page 1-10
• Global-active device and server I/O on page 1-14
Global-active device and server I/O
I/O requests from the server to a GAD pair volume are managed according to
the volume's I/O mode. The GAD status determines the I/O mode of the P-
VOL and S-VOL of a pair. This topic provides a detailed description of read
and write I/O processing for each GAD status.
Related topics
•
Server I/O when the GAD status is Mirrored on page 1-15
• Server I/O when the GAD status is Mirroring on page 1-15
• Server I/O when the GAD status is Suspended on page 1-16
• Server I/O when the GAD status is Blocked on page 1-17
• Monitoring GAD status on page 1-10
1-14
Overview of global-active device
Hitachi Virtual Storage Platform G1000 Global-Active Device User Guide