Enabling SnapMirror network compression

You can enable network compression for a volume SnapMirror relationship by specifying the compression option in the snapmirror.conf file.

Before you begin

You must have ensured that the compression feature is supported only for asynchronous volume SnapMirror.
You must have ensured that the SnapMirror destination system should be using a Data ONTAP release that supports SnapMirror network compression. Data ONTAP 7.3.2 and later releases of the 7.x release family, and Data ONTAP 8.0.1 and later releases of the 8.x release family support SnapMirror network compression.

About this task

There are certain considerations for enabling and disabling SnapMirror network compression.

To enable compression, you must specify a name for the connection between a SnapMirror source and destination system pair.
You can enable or disable compression for both initial and incremental SnapMirror transfers.
You need to enable the compression feature on a per-relationship basis.
You cannot enable or disable compression for an active SnapMirror transfer.
However, the transfers that get activated after you edit the snapmirror.conf file use the updated compression configuration. If you want the change in the option to be applied immediately, enter the following command:

snapmirror on

Steps

Open the snapmirror.conf file.
Specify the SnapMirror relationship by using the following command:
connection_name=mode(src_system-e0,dst_system-e0)(src_system-e1,dst_system-e1)
connection_name:src_vol dst_system:dst_vol - * * * *
connection_name is the name of this specific connection between a SnapMirror source and destination system pair.

mode is the mode of the connection. It can either be multi or failover.

src_system-e0 and src_system-e1 are the names of the SnapMirror source systems.

dst_system-e0 and dst_system-e1 are the names of the SnapMirror destination systems.

src_vol is the path of the SnapMirror source volume.

dst_vol is the path of the SnapMirror destination volume.

Enable compression by adding the compression=enable option to the SnapMirror relationship specification.

The syntax of the entries in the snapmirror.conf file required for enabling compression is given in the following lines:

connection_name=mode(src_system-e0,dst_system-e0)(src_system-e1,dst_system-e1)

connection_name:src_vol dst_system:dst_vol compression=enable * * * *

Example

conxn_1=multi(src_system,dst_system)
conxn_1:src_vol dst_system:dst_vol compression=enable * * * *

Example

The following example shows the SnapMirror relationship status, SnapMirror log files on both the source and the destination systems, and the compression ratio:

SnapMirror relationship status

f3070-202-xx*> snapmirror status -l
Snapmirror is on.

Source:                 f3070-202-xx:src
Destination:            f3070-202-yy:dst
Status:                 Transferring
Progress:               1687772 KB
Compression Ratio:      2.6 : 1
State:                  Source
Lag:                    -
Mirror Timestamp:       -
Base Snapshot:          -
Current Transfer Type:  -
Current Transfer Error: -
Contents:               -
Last Transfer Type:     -
Last Transfer Size:     -
Last Transfer Duration: -
Last Transfer From:     -

SnapMirror log file on source system

log Wed May 19 07:04:17 GMT FILER_REBOOTED
sys Wed May 19 07:10:31 GMT SnapMirror_on (registry)
src Wed May 19 08:55:56 GMT f3070-202-xx:src f3070-202-yy:dst Request (10.**.***.**)
src Wed May 19 08:55:56 GMT f3070-202-xx:src f3070-202-yy:dst Abort (connection to destination dropped)
src Wed May 19 09:08:54 GMT f3070-202-xx:src f3070-202-yy:dst Request (10.**.***.**)
slk Wed May 19 09:08:55 GMT state.softlock.src.00000022.002.f3070-202-yy:dst Softlock_add (Transfer)
src Wed May 19 09:08:55 GMT f3070-202-xx:src f3070-202-yy:dst Start
src Wed May 19 09:10:16 GMT f3070-202-xx:src f3070-202-yy:dst End (1687772 KB, Compression 2.6 : 1)

SnapMirror log file on destination system

sys Mon May 17 03:58:06 GMT SnapMirror_off (shutdown)
log Mon May 17 04:04:06 GMT FILER_REBOOTED
slk Mon May 17 10:33:32 GMT state.softlock.newvol.00000012.002.snapmirror_tape_f8568c4a-6331-11df-80d6-00a0980c07a7 Softlock_add (Transfer)
src Mon May 17 10:33:32 GMT f3070-202-40:newvol f3070-202-yy:/etc/pqr Request (Store)
src Mon May 17 10:33:32 GMT f3070-202-40:newvol f3070-202-yy:/etc/pqr Start
src Mon May 17 10:33:32 GMT f3070-202-40:newvol f3070-202-yy:/etc/pqr End (344 KB)
sys Wed May 19 06:45:11 GMT SnapMirror_off (shutdown)
log Wed May 19 06:48:07 GMT FILER_REBOOTED
sys Wed May 19 08:53:44 GMT SnapMirror_on (registry)
dst Wed May 19 08:59:40 GMT conn:src f3070-202-yy:dst Request (Initialize)
dst Wed May 19 08:59:42 GMT conn:src f3070-202-yy:dst Abort (replication transfer failed to complete)
dst Wed May 19 09:12:38 GMT conn:src f3070-202-yy:dst Request (Initialize)
dst Wed May 19 09:12:40 GMT conn:src f3070-202-yy:dst Start
dst Wed May 19 09:14:01 GMT conn:src f3070-202-yy:dst End (1687772 KB, Compression 2.6 : 1)

The data shown in the above log files is pre-compression data.

Note: To disable compression, remove the compression=enable option from the SnapMirror relationship entry in the snapmirror.conf file.

Compression for a multipath SnapMirror relationship

The syntax of the entries in the snapmirror.conf file required for enabling compression for a multipath SnapMirror relationship is given in the following lines:

connection_name=multi(src_ip1,dst_ip1)(src_ip2,dst_ip2)

connection_name:src_vol dst_system:dst_vol compression=enable * * * *

src_ip1 and src_ip2 are the IP addresses of the SnapMirror source system.

dst_ip1 and dst_ip2 are the IP addresses of the SnapMirror destination system.

conxn_2=multi(10.72.146.74,10.79.106.40)(10.72.147.74,10.79.107.40)
conxn_2:src_vol dst_system:dst_vol compression=enable * * * *

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