Dell EMC Solutions Enabler 9.2 SRDF Family CLI User Guide

In adaptive copy write pending (acp_wp) mode, the array acknowledges all writes to the source (R1) device as if it is a local device.

The amount of data (number of tracks) out of synchronization between the R1 and the R2 devices at any given time is determined by the maximum skew value. You can set the maximum skew value using SRDF software.

New data accumulates in cache until it is successfully written to the source (R1) device and the remote director has transferred the write to the target (R2) device.

This SRDF mode is designed to have little or no impact on performance between the host and the array containing the source (R1) device.

HYPERMAX OS

Adaptive copy write pending mode is not available when the R1 side of the pair is on an array running HYPERMAX OS.

HYPERMAX OS/Enginuity 5876 backward compatibility

In SRDF configurations where R1 devices are on an array running HYPERMAX OS, connected to one or more arrays are running Enginuity 5876, the following restrictions apply:

• For swap and failover operations - If the R2 is on an array running HYPERMAX OS, and the mode of the R1 is adaptive copy write pending mode, SRDF sets the mode to adaptive copy disk.
• For migrate -replace R1 operations - If the R1 being replaced is on an array running HYPERMAX OS, and the mode of the R1 is adaptive copy write pending mode, SRDF sets the mode of the migrated pair to adaptive copy disk.

Examples

To set the replication mode in group prod to adaptive copy write pending:

symrdf -g prod set mode acp_wp

To disable adaptive copy write pending and set the replication mode in group prod to synchronous:

symrdf -g prod set mode acp_off