Hitachi TAGMASTORE MK-90RD011-25 User Manual

Page 37

Hitachi Command Control Interface (CCI) User and Reference Guide

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 status 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

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

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

when using

write enable

pairsplit option

PSUE

(error)

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