ShadowImage operations and global-active device pair status

Ops Center High Availability User Guide
Version
10.9.x
File Size
3.9 MB
Audience
anonymous
Part Number
MK-99ADM003-14

The ability to perform a SI pair operation depends on the SI pair status and GAD pair status.

The following tables show SI pair operations and whether they can be performed (Yes, No) with the listed GAD status. The information assumes the required SI status for the operation.

The Virtual LDEV ID column shows whether the volume has a virtual LDEV ID or not (Yes, No).

Table. ShadowImage operations when global-active device status is Simplex

GAD pair status

Virtual LDEV ID

I/O

ShadowImage pair operation

Read

Write

Create pairs

Split pairs

Resync pairs

Restore pairs

Delete pairs/Suspend copy

SMPL

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

Yes

Yes

Yes

Yes

Yes

No, but the GAD reserve attribute is set

No

No

No

No

No

No

Yes

Table. ShadowImage operations when global-active device status is Mirroring

GAD pair status

I/O mode

Pair location

I/O

ShadowImage pair operation

Read

Write

Create pairs

Split pairs

Resync pairs

Restore pairs

Delete pairs/Suspend copy

INIT/COPY

Mirror (RL)

Primary

Yes

Yes

Yes

Yes

Yes

No1

Yes

Block

Secondary

No

No

Yes

No2

No2

No1, 3

Yes

COPY

Mirror (RL)

Primary

Yes

Yes

Yes

Yes

Yes

No1

Yes

Block

Secondary

No

No

Yes

No2

No2

No1, 3

Yes

Notes:

  1. Cannot be used because GAD pairs are not suspended.
  2. Cannot be used because S-VOL data is not fixed.
  3. Cannot be used because the volume at the GAD copy destination is the same as the volume at the ShadowImage copy destination.
Table. ShadowImage operations when global-active device status is Mirrored

GAD pair status

I/O mode

Pair location

I/O

ShadowImage pair operation

Read

Write

Create pairs

Split pairs

Resync pairs

Restore pairs

Delete pairs/Suspend copy

PAIR

Mirror (RL)

Primary

Yes

Yes

Yes

Yes

Yes

No*

Yes

Secondary

Yes

Yes

Yes

Yes

Yes

No*

Yes

* Cannot be used because GAD pairs are not suspended, and also because the volume at the GAD copy destination is the same as the volume at the ShadowImage copy destination.

Table. ShadowImage operations when no volume is set for the quorum disk or global-active device status of global-active device pairs

GAD pair status

I/O mode

Pair location

I/O

ShadowImage pair operation

Read

Write

Create pairs

Split pairs

Resync pairs

Restore pairs

Delete pairs/Suspend copy

PAIR

Mirror(RL)

Primary

Yes

Yes

Yes

Yes

Yes

No*

Yes

Mirror(RL)

Secondary

Yes

Yes

Yes

Yes

Yes

No*

Yes

* Cannot be used because GAD pairs are not suspended, and also because the volume at the GAD copy destination is the same as the volume at the ShadowImage copy destination.

Table. ShadowImage operations when global-active device status is Suspended

GAD pair status

I/O mode

Pair location

I/O

ShadowImage pair operation

Read

Write

Create pairs

Split pairs

Resync pairs

Restore pairs

Delete pairs/Suspend copy

PSUS

Local

Primary

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Block

Primary

No

No

Yes

Yes

Yes

No

Yes

PSUE

Local

Primary

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Block

Primary

No

No

Yes

Yes

Yes

No

Yes

Secondary

No

No

Yes

Yes

Yes

No

Yes

SSUS

Block

Secondary

No

No

Yes

Yes

Yes

No

Yes

SSWS

Local

Secondary

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Table. ShadowImage operations when global-active device status is Blocked

GAD pair status

I/O mode

Pair location

I/O

SI pair operations

Read

Write

Create pairs

Split pairs

Resync pairs

Restore pairs

Delete pairs/Suspend copy

PSUE

Block

Primary

No

No

Yes

Yes

Yes

No

Yes

Secondary

No

No

Yes

Yes

Yes

No

Yes