What I once did, (on a cache-only system) was;
Nightly cron job on the "current" (old/source) server doing DB2 exports into files with DB2MOVE + DB2LOOK,
then rsync of the database exports and cache file systems,
On the receiving (new/target) server, another cron job that re-created the DB2 database from the export files, and then performed a CMOD DB version upgrade (because why not
)
Then we had time to test the new installation with current contents, and we even did the all new loads/ingestions in both systems for a while (with the older system being mandatory, since the new one was being rebuilt each night).
When we were satisfied that the new system was functional and reliable, we stopped syncing and killed the old server.
I'm not saying that this is how it should be done, but it worked very well for us. The rsync was very useful since we had a lot of data (being a cache-only setup with everything online on disk), and didn't want a very long downtime to make the switch.