The /etc/snapmirror.conf file

Purpose of the snapmirror.conf file

The /etc/snapmirror.conf file resides on the destination filer. It controls where data is copied and how often a mirror is updated.

The filer is not shipped with a default /etc/snapmirror.conf file. You must use a text editor to create the file if you want to use SnapMirror.

When you can modify the snapmirror.conf file

You can modify the /etc/snapmirror.conf line at any time.

Format of the snapmirror.conf file

Each entry of the /etc/snapmirror.conf file is in the following format:

source_filer:source_vol destination_filer:destination_vol argument schedule

Meaning of each field in a snapmirror.conf entry

The following list describes the meaning of each field in a snapmirror.conf entry:

source_filer is the host name of the filer from which data is replicated.
source_vol is the source volume name. For example, for the vol1 volume, type vol1. Do not type the full path name (/vol/vol1).
destination_filer is the host name of the filer to which data is replicated.
destination_vol is the destination volume (mirror) name. For example, for the vol1 volume, type vol1. Do not type the full path name (/vol/vol1).
argument is kbs (kilobytes per second), the maximum speed at which data is transferred. Enter a value greater than or equal to 11. By default, the filer transfers the data as fast as it can. Enter a dash (-) to indicate that you want to use the default value for argument.

Note: The actual data transfer speed might be limited by factors such as network bandwidth. For example, if you specify a large value such as 1,000,000, the filer might still transfer the data at 2,000 kilobytes per second.
schedule is the schedule used by the destination filer for updating the mirror.

You must not leave any field in a snapmirror.conf entry blank. If you do not want to specify the maximum speed for data transfer, specify a dash as the argument.

Rules for specifying the update schedule

The schedule in each /etc/snapmirror.conf entry contains four fields:

minute
hour
day of month
day of week

The fields are separated from each other by a space. If a field contains more than one value, the values are separated from each other by a comma. A field containing an asterisk (*) means that the field is irrelevant. If you specify an asterisk in each field of the schedule, the filer updates the mirror every minute.

The update schedule is mandatory. The filer generates an error message if a /etc/snapmirror.conf entry does not contain a schedule.

Example

filerA:vol1 filerB:vol2 kbs=2000 45 10,11,12,13,14,15,16 
* 1,2,3,4,5

In this example, /vol/vol1 on filerA is replicated to /vol/vol2 on filerB. Data is replicated at a maximum rate up to 2,000 kilobytes per second. FilerB updates /vol/vol2 at 10:45 a.m., 11:45 a.m., 12:45 p.m., 1:45 p.m., 2:45 p.m., 3:45 p.m., and 4:45 p.m., Monday through Friday. The asterisk in this example means that the mirror update schedule is not affected by the day of month.

When changes to snapmirror.conf take effect

If SnapMirror is enabled, the changes take effect within two minutes. If SnapMirror is disabled, the changes take effect immediately after you enter the vol snapmirror on command to enable the feature.

Recommendation

You can create a single /etc/snapmirror.conf file for your site and copy it to all the filers that use SnapMirror. The /etc/snapmirror.conf file can contain entries pertaining to other filers. For example, the /etc/snapmirror.conf file on filerB can contain an entry for replicating a volume from filerC to filerD. When filerB reads the /etc/snapmirror.conf file, it simply ignores this entry.

Part No. 210-02334
File: mirror7.htm
Last updated: 04/26/99 08:11:54