Hitachi Command Control Interface (CCI) User and Reference Guide 19
2.4.1 TrueCopy/ShadowImage/Universal Replicator Volume Status
Each TrueCopy pair consists of one P-VOL and one S-VOL, and each ShadowImage pair
consists of one P-VOL and up to nine S-VOLs when the cascade function is used.
Table 2.1 lists and describes the Hitachi TrueCopy and ShadowImage pair st
atus terms. The
P-VOL controls the pair status for the primary and secondary volumes. The major pair
statuses are SMPL, PAIR, PSUS/PSUE, and COPY/RCPY. Read and write requests from the host
are accepted or rejected depending on the pair status of the volume.
The pair status can change when a CCI command is executed. The validity of the specified
operation is checked according to the status of the volume (primary volume).
Table 2.2 shows the relationship between pair status and TrueCopy/Universal Replicator
command acceptance.
Table 2.3 shows the relationship between pair status and ShadowImage command
acceptance.
Table 2.4 shows the relationship between pair status and COW Snapshot command
acceptance.
Table 2.1 Hitachi TrueCopy and ShadowImage Pair Status
Status Hitachi TrueCopy Pair Status ShadowImage Pair Status Primary Secondary
SMPL Unpaired volume Unpaired volume R/W enabled R/W enabled
PAIR Paired volume. Initial copy is complete.
Updates are processed synchronously
or asynchronously.
Paired volume. Initial copy is complete.
Updates are processed
asynchronously.
R/W enabled R enabled
COPY In paired state, but initial copy, pairsplit,
or resync operation is not complete.
Includes COPY(PD), COPY(SP), and
COPY(RS) status.
In paired state, but initial copy, pairsplit,
or resync operation is not complete.
Includes COPY(PD), COPY(SP), and
COPY(RS) status.
R/W enabled R enabled
RCPY Not used for Hitachi TrueCopy In paired state, but reverse resync
operation is not complete. Includes
COPY(RS-R) status.
R enabled R enabled
PSUS
(split)
In paired state, but updates to the
S-VOL data are suspended due to user-
requested pairsplit. The RAID storage
system keeps track of P-VOL and
S-VOL updates while the pair is split.
In paired state, but updates to the
S-VOL data are suspended due to user-
requested pairsplit. The RAID storage
system keeps track of P-VOL and
S-VOL updates while the pair is split.
R/W enabled R/W enabled
when using
write enable
pairsplit option
PSUE
(error)
or
PFUS
In paired state, but updates to the
S-VOL data are suspended due to an
error condition. (PSUE is PSUS with
reason of internal error. PFUS is PSUS
with reason of sidefile full.)
In paired state, but updates to the
S-VOL volume data are suspended due
to an error condition. When a PSUE
pair is resynched, the RAID storage
system copies the entire P-VOL to the
S-VOL (same as initial copy).
R/W enabled if
no error occurs
in the primary
volume
R enabled
PDUB Used for Hitachi TrueCopy LUSE pairs
only. In paired state, but updates to one
or more LDEVs within the LUSE pair
are suspended due to error condition.
Not used for ShadowImage R/W enabled if
no error occurs
in the primary
volume
R enabled
