L1, L2 pair status and supported pair tasks

ShadowImage User Guide

Version
9.8.7
Audience
anonymous
Part Number
MK-98RD9021-17

The pair tasks you can complete on cascaded pairs depend on the L1 and L2 pair status. The tasks are dependent on the following:

  • To perform an L1 pair task, the status of the L2 pair.
  • To perform an L2 pair task, the status of the L1 pair.
  • Supported read/write on L1 and L2 S-VOLs.

The following table lists the L1 pair tasks that you can complete based on the related L2 status.

L2 pair status L1 pair task
Create pairs Split pairs Resync pairs

(Normal copy)

Resync pairs

(Reverse copy)

Suspend pairs Delete pairs
COPY(PD)/COPY Yes Yes Yes Yes Yes Yes
PAIR Yes Yes Yes Yes Yes Yes
COPY(SP)/COPY No No No No Yes Yes
PSUS(SP)/PSUS No No No No Yes Yes
PSUS Yes Yes Yes Yes Yes Yes
COPY(RS)/COPY Yes Yes Yes Yes Yes Yes
PSUE Yes Yes Yes Yes Yes Yes

The following table lists the L2 pair tasks that you can perform based on the related L1 status.

L1 pair status

L2 pair task

Create pairs

Split pairs

Resync pairs (Normal Copy)1

Resync pairs (Reverse Copy)1

Suspend pairs

Delete pairs

COPY(PD)/COPY YES NO YES NO YES YES
PAIR YES NO YES NO YES YES
COPY(SP)/COPY YES NO YES NO YES YES
PSUS(SP)/PSUS NO NO YES NO YES YES
PSUS YES

YES2

YES NO YES YES
COPY(RS)/COPY YES NO YES NO YES YES
COPY(RS-R)/RCPY YES NO YES NO YES YES
PSUE YES NO YES NO YES YES
  1. For L2 pairs, only Normal Copy or Quick Resync can be performed. You cannot perform a reverse resynchronization (Reverse Copy or Quick Restore). For more information about resynchronizing L2 pairs, see Resynchronizing or restoring ShadowImage pairs.
  2. To split L2 pairs, the L1 pair status must be PSUS. For more information about the prerequisites for splitting L2 pairs, see Splitting ShadowImage pairs.

The following table lists the node volume read/write L1 and L2 pair status.

L1 Pair Status

L2 pair status

COPY(PD)/COPY

PAIR

COPY(SP)/COPY

PSUS(SP)/PSUS

PSUS

COPY(RS)/COPY

PSUE

COPY(PD)/COPY

Read only

Read only

Read only

Read only

Read only

Read only

Read only

PAIR

COPY(SP)/COPY

PSUS(SP)/PSUS

Read/Write

Read/Write

Read/Write

Read/Write

Read/Write

Read/Write

Read/Write

PSUS

COPY(RS)/COPY

Read only

Read only

Read only

Read only

Read only

Read only

Read only

COPY(RS-R)/RCPY

PSUE

The following table lists the leaf vol read/write per L2 pair status.

L2 pair status

COPY(PD)/COPY

PAIR

COPY(SP)/COPY

PSUS(SP)/PSUS

PSUS

COPY(RS)/COPY

PSUE

Read only

Read only

Read only

Read/Write

Read/Write

Read only

Read only