Hitachi TAGMASTORE MK-90RD011-25, Руководство пользователя

Страница: 39 / 388

Hitachi Command Control Interface (CCI) User and Reference Guide 21
Table 2.3 Pair Status versus ShadowImage Commands
ShadowImage Command
Paircreate Pairsplit Pairresync
Pair Status No -split -split -E option -C option -S option Resync
c
SMPL Accepted
d
Accepted [2]
dÆf
Rejected Rejected Acceptable Rejected
d
COPY
RCPY
Acceptable Accepted [1]
dÆf
Accepted
g
Accepted [1]
dÆf
Accepted
c
Acceptable
e
PAIR Acceptable Accepted [2]
dÆf
Accepted
g
Accepted [2]
dÆf
Accepted
c
Acceptable
f
PSUS Rejected Acceptable Accepted
g
Acceptable Accepted
c
Accepted
d
g PSUE Rejected Rejected Acceptable Rejected Accepted c Accepted d
Note: If the PVOL does not have Write in the PAIR state, then data identical with an SVOL is
guaranteed. Therefore, in case of using the SVOL with the SMPL state, after stopping Write
to the PVOL, generate a paired volume, and then split the paired volume after confirming
that the paired volume has the PAIR status. In the PSUE state, ShadowImage does not
manage differential data at the PVOL or SVOL. 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%”.
Note 1:
The state change ( dÆf ) is effective COPY state only that is changed without
specification of -split for paircreate command.
Note 2: The (
d
Æ
f
) state change is displayed as PVOL_PSUS & SVOL_COPY (see display
example below), and reading and writing are enabled for SVOL 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 will attempt to read non-reflected data on SVOL in PVOL_PSUS & SVOL_COPY state, then HOMRCF copies non-
reflected data from PVOL to SVOL, and will be returned the correct data after copied. This will brings the performance
degradation (1/6 to 1/15 with IOPS) to read on the SVOL.
– If you will attempt to write non-reflected data on SVOL in PVOL_PSUS & SVOL_COPY state, then HOMRCF copies non-
reflected data from PVOL to SVOL, and writing data is managed as delta data for SVOL after copied. This will brings the
performance degradation (1/6 to 1/8 with IOPS) to write on the SVOL.
– If you will attempt to write to the data on PVOL that does not still reflected the data to SVOL, then HOMRCF copies non-
reflected data from PVOL to SVOL, and writing data is managed as delta data for PVOL. This will brings the performance
degradation (1/6 to 1/8 with IOPS) to write on the PVOL.