If you are replicating from IBM Db2 for i (iSeries/AS400) using mirroring mode, you can improve performance by setting a block size for reading data from the journal.
The block size setting is useful if you expect a huge number of transactions between mirrorings. Syniti Replicatereads the journal and stores records that need to be replicated in a temporary file. If the file contains a large number of records or a smaller number of very large records, it can impact performance. In this case, you can set a limit on the number of records to handle at one time. For example, if you set the value of the MaxSizeMirroringBlock property in the Connection Properties to 250, only 250 records will be replicated at a time.
In the Management Center, expand the tree to display your Db2 for i (iSeries/AS400) source connection.
From the right mouse button menu, choose Connection Properties.
Scroll down to the MaxSizeMirroringBlock property.
Set the value of the property according to the size of your records and the number of records you are likely to be mirroring.
Click OK to close the Connection Properties dialog.
If the replication is already running, for this change to take effect, you will need to disable, then re-enable the replication.