As described in Print jobs and print files, PSF Input Manager segments AFP files so printing can start before a job completes ripping. The smaller the segments, the faster PSF starts printing the job. However, if the pieces get too small, there will be too many files and too much disk thrashing. If PSF has to open a new file for each page that can slow things down significantly.
The default setting of 5000KB for each segment can be raised to reduce
the disk I/O associated with reading and writing data to the
system; however, the default setting usually works well with most AFP production
The InfoPrint Manager SMIT Customize
the Input Manager panel (
→ Miscellaneous → Customize the Input Manager) lets you change
the default segment size. The segment size parameter determines the maximum
size of any temporary file created by the Input Manager component of InfoPrint Manager that is stored
/var/psf/segments. This parameter should only be
adjusted when there is a problem with throughput.
Since there are so many small files stored in
you might think you should change the fragment size of the file system to
allow for better space utilization. However, for better performance, it is
best to set the fragmentation size at its highest value of 4096 bytes because
a smaller size might increase disk I/O operations.
By default, segments are deleted when they are no longer needed by PSF.
You can specify no with the delete-segment-list job attribute
to retain the segments. You might want to do this if you are reprinting the
job. When segments are retained, Input Manager automatically manages the space
/var/psf/segments. By default, fifty percent of
the space will be allotted for retained segments. The Customize the Input
Manager SMIT panel can also be used to change this value. A higher value
will cause Input Manager to retain more print data in the system to extend
the range of re-start and rerun job management functions. However, a higher
value might cause printer clutching since there will be less room for the
printing jobs segments.