HP XP7 Storage - Manual (Page 159)

Table 33 Pair status versus Business Copy commands (continued)
Business Copy command -
pairresync pairsplit paircreate
Resync -S option -C option -E option -split No -split Pair Status
Acceptable Accepted 1 Accepted [2] 2
to 4 Accepted 5 Accepted [2] 2
to4 Acceptable PAIR 3
Accepted 2 Accepted 1 Acceptable Accepted 5 Acceptable Rejected PSUS 4
Accepted 2 Accepted 1 Acceptable Acceptable Acceptable Rejected PSUE 5
Legend:
Accepted = Accepted and executed. When the operation terminates normally, the status changes to the indicated number.
Acceptable = Accepted but no operation is executed.
Rejected = Rejected and operation terminates abnormally.
In the following descriptions, when the pair statuses of P-VOL and S-VOL are different, PVOL_ or
SVOL_ are applied to show which volume is indicated.
NOTE: If the P-VOL does not have Write in the PAIR state, then data identical with an S-VOL is
guaranteed. Therefore, when using the S-VOL with the SMPL state, after stopping Write to the
P-VOL, generate a paired volume, and then split the paired volume after confirming that the paired
volume has the PAIR status. In the PSUE state, Business Copy does not manage differential data at
the P-VOL or S-VOL. Therefore, pairresync issued to a pair in the PSUE state is all copy performance,
but the copy progress rate returned by the -fc option of the pairdisplay command indicates "0%".
[1]: The state change (2 to 4) is effective for only the COPY state that is changed without
specification of -split for paircreate command.
[2]: The (2 to 4) state change appears as P-VOL_PSUS & S-VOL_COPY (see example below), and
reading and writing are enabled for S-VOL in SVOL_COPY state.
# pairsplit -g oradb
# pairdisplay -g oradb -fc
Group PairVol(L/R) (Port#,TID,LU-M), Seq#, LDEV#.P/S, Status, %, P-LDEV# M
oradb oradev3(L) (CL2-N, 3, 4-0) 8071 28..P-VOL PSUS, 100 29 W
oradb oradev3(R) (CL2-N, 3, 5-0) 8071 29..S-VOL COPY, 97 28 -
PVOL_PSUS & SVOL_COPY is the non-reflected PSUS state that data is still being copied from the
P-VOL to the S-VOL, and this state has the following specific behavior.
•
If you attempt to read non-reflected data on SVOL in PVOL_PSUS & SVOL_COPY state, then
Business Copy copies non-reflected data from PVOL to SVOL, and returns the correct data
after copied. This will bring the performance degradation (1/6 to 1/15 with IOPS) to read
on the SVOL.
•
If you attempt to write non-reflected data on SVOL in PVOL_PSUS & SVOL_COPY state, then
Business Copy copies non-reflected data from PVOL to SVOL, and writing data is managed
as delta data for SVOL after copied. This will bring the performance degradation(1/6 to 1/8
with IOPS) to write on the SVOL.
•
If you attempt to write to the data on PVOL that does not still reflected the data to SVOL, then
Business Copy copies non-reflected data from PVOL to SVOL, and writing data is managed
as delta data for PVOL. This will bring the performance degradation(1/6 to 1/8 with IOPS)
to write on the PVOL.
•
The state changes for pairsplit are (WD = Write Disable, WE = Write Enable):
Continuous Access Synchronous, Business Copy, and Continuous Access Journal operations 159