RDF System Management Manual for J-series and H-series RVUs (RDF Update 13)

Figure 6 Receiver Process Operation
56 KB Buffers
56 KB Buffers
Receiver
From Extractor
56KB per message
Expand Lines
56 KB Buffers
56 KB BuffersUpdater
Updater
Updater
Back up Node
Database
Volumes
Database
Volumes
Database
Volumes
Disk 1
(1st Image Trail)
Disk 2
(2nd Image Trail)
Disk n
(nth Image Trail)
Audit data stored by
destination volume,
transmitted by 56KB writes
AAnnnnn
AAnnnnn and BBnnnnn
Image
File
Image
File
Image
File
Master
Image
File
With sorted image trails, the activity of any one image file typically remains so low that it can be
stored on the same disk volumes as the main database with no significant I/O impact. This approach
is not recommended, however, if you require very high RDF performance or if RDF is running with
the UPDATE option turned off; in this case, the image trails could eventually fill the volume; in such
cases, it is best to have volumes exclusively dedicated to the image trails.
NOTE: You should keep all image trail files off of the $SYSTEM volume and its controller.
Otherwise, if there is a lot of audit data to send from the primary system to the backup system, it
could take a while for the updaters to start.
36 Introducing RDF