SAVLIB
and SAVOBJ
in V5R4 and higher support the SPLFDTA parameter.  That’s how I back up
spool file data on a daily basis.

A simple method of archiving spool file data is to create a library, create
output queues within that library, move the spool files you want to
library/output queues, then save the lot.

There are other tools out there but I don’t have any familiarity with
them.  I’m certain others here do.[This is my third attempt to post a response - if this shows up as duplicate I apologise, but my previous attempts aren't displaying at all.]

I would first recommend going to the V5R4 Innformation Center and typing [ restore and spool ] into the search field above the left-hand navigation pane. Everything anybody knows about system functions for this question comes from those search results.
 
The first couple search results give some of the best information. You get to the Commands to save/restore spooled files and Saving and restoring spooled files pages. (Both of those might be listed as ‘Saving and restoring spooled files’ in the search results.)
 
IMO, the biggest ‘trick’ is simply not to save spooled files unless there is a legal/compliance/regulatory requirement to do so. A spooled file is intended to be printed and used. If there’s no intent to print it for use, there is generally no reason to generate it in the first place. Don’t generate spooled files that won’t be used.
 
A spooled file isn’t important enough to save without legal reason.
 
What is important is the data that is used and the process that presents the data. If spooled files are being generated and saved in some significant volume, the applications are not designed appropriately or are being used incorrectly.
 
Also, the system accounting journal can be used to track generation and printing of spooled files. When combined with the system audit journal, a strong audit trail is available.
 
Maybe the best ‘tip’ is to leave V5R4 behind and get up to i 6.1 at least. You could convert spooled files to .PDFs at V5R4 and store the .PDFs, but should be easier at 6.1.
 
The main question would be why the spooled files need to be saved in the first place. If it’s just saving for the sake of saving, I wouldn’t do it at all. If users are creating spooled files for no good reason, I’d be running regular purges and deleting them after a few days.
 
If a given spooled file must be saved for legal reasons, I’d use as much of system functions as possible to do the save work along with system job accounting and auditing.
 
Tom

@Splat: You had links in your comment. If links are approved, the comment should show up later. It can take a while sometimes, and it can seem like the comment is lost. — Tom

Tom, thanks for the information.  I had no idea what was happening and, yes, I did think the comments were disappearing.