Chapter 6. LREP and SnapMirror 101
6.2 Data center
All steps in this section are issued at the data center unless noted otherwise.
Once the lrep_reader files have been successfully dumped to tape and those
tapes have been successfully transferred to the data center, it is time to restore
them to filerB (which is also a storage system in the example).
Make the files created by lrep_reader available on client2 (which should have
lrep_writer installed). In this example you are accessing the files via NFS. Read
permission is necessary only for these files on client2. You assume that these
files have been restored to vol2 on filerB.
Mount vol2 from filerB on client2, as in Example 6-8. You will delete temporary
files, so mount it r/w.
Example 6-8 Mounting vol2 from client2
client2% mkdir -p /t/filerB/vol2
client2% mount -o rw filerB:/vol/vol2 /t/filerB/vol2
Run lrep_writer by specifying protocol (SnapMirror) and the logical replication
file name prefix. In this example, use /t/filerB/vol2/lrep_dump/lrep_srcqtree as
the file name's prefix. lrep_writer then reads the logical replication stream from
lrep_srcqtree.0, lrep_srcqtree.1, and so on until the last file in this continuous
sequence (Example 6-9).
Example 6-9 lrep_writer command
client2% lrep_writer -p snapmirror_init
Waiting for connection.
If file_name is specified as source of the logical replication stream, lrep_writer
looks for file_name.0, file_name.1, file_name.2, and so on, until it fails to find a
file in this sequence. It assumes the end of stream at that point.
If there are files containing logical replication streams spread across multiple
directories, give multiple paths to lrep_writer.
Now start the transfer from filerB to read the logical replication stream data from
client2 (Example 6-10).
Example 6-10 Initialize snapmirror
filerB> snapmirror initialize -S client2:/vol/srcvol/srcqtree
102 IBM System Storage N Series SnapMirror
Transfer started. Monitor progress with ‘snapmirror status' or the
On client2, the output in Example 6-11 is present.
Example 6-11 Output in client2
Waiting for connection.
Connection accepted from filerB.
Use 'snapmirror status' on filer to monitor progress.
Verify by using 'snapmirror status' on filer.
The SnapMirror baseline transfer is now done (seeded). It is time to replicate
data directly from filerA to filerB. From this point on use the snapmirror update
-S filerA:/vol/dstvol/dstqtree command on filerB to transfer incremental
changes from filerA to filerB. Or, add an /etc/snapmirror.conf entry with a
schedule for the new SnapMirror relationship to make it a permanent, scheduled
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