CTG 127 behavior and restrictions when a pair is suspended
Note the following behaviors and restrictions regarding the consistent
suspending of all P-VOLs when a pair suspends.
• When a failure occurs or if a pair is suspended by CCI, all P-VOLs will be
suspended.
• When P-VOLs and S-VOLs are registered in CTG 127, and both volumes
are paired bi-directionally, all of the target pair volumes are registered in
CTG No.127 when takeover takes place.
• The maximum number of pairs in CTG 127 is 4,096.
• For P-VOLs to be suspended, a failure must occur, and then a write I/O
operation must occur in any of the pairs.
• When P-VOL status is PAIR and S-VOL status is PSUE, if a write I/O is
executed, all P-VOLs registered in CTG 127 are suspended by failure.
When P-VOL status is PAIR and S-VOL status is PSUE, you can restore
PAIR status to the S-VOL by suspending the P-VOL and then
resynchronizing the pair. With CCI, use the -l option.
• When the S-VOL is suspended due to an intermittent communication
failure, the P-VOL might not be suspended (P-VOL with no I/O processing
stays in PAIR).
CTG 127 behavior and restrictions when the data path fails
Note the following behaviors and restrictions regarding the consistent
changing of all S-VOLs to PSUE status when the secondary system is
disconnected.
• S-VOLs must be in PAIR or COPY status in order to change to PSUE
status. They cannot be in PSUS or SSUS status.
• All connections to the primary system must be disconnected.
S-VOLs cannot be changed to PSUE status if the MinimumPath field is set
to a value other than 1 on the primary system (RCU Option dialog box).
• Changing status to PSUE may take up to 10-minutes if there are many
pairs.
• All S-VOLs will be changed to PSUE even if all data paths are recovered in
the middle of the process.
• If the data paths are disconnected for a short time (less than one
minute), S-VOLs may not change to PSUE status because the storage
system does not detect the disconnection.
• After a power outage, all S-VOLs registered in CTG 127 will be changed to
PSUE status.
• If write I/O is executed when the P-VOL is in PAIR status and the S-VOL is
in PSUE status, the secondary system does not accept updates, and the
primary system suspends the P-VOL.
• Remote I/O (RIO), which is issued during the change to PSUE status, is
accepted by the secondary system.
• When a pair's status is changing to PSUE:
3-24
Planning for TrueCopy
Hitachi TrueCopy® User Guide for Hitachi Virtual Storage Platform Gx00 and Fx00 Models
To Next Page
Loading...
