In each SAVxxx command by pressing function key F10 (Additional parameters) you can see some pages below a field named DTACPR "Data compression".
The default value for this field is *DEV. By saving the object in a save file the default value has no influence i.e. no data compression is performed.
But, by changing the default value from *DEV to *YES (only allowed if you save in a *SAVF) you'll gain up to 40% space and also time for sending and restoring on the remote system.
I made the following test on my system:
My library SAUVAJE1 uses 243 MB space.
SAVLIB LIB(SAUVAJE1) DEV(*SAVF) SAVF(QTEMP/JMS) the space used by the *SAVF is 243 MB
- SAVLIB LIB(SAUVAJE1) DEV(*SAVF) SAVF(QTEMP/JMS)DTACPR(*YES)
The space used by the *SAVF by specifying DTACPR(*YES) is now 136 MB. The space reduction is 44 %.
Also, the time needed to send the *SAVF on the remote system and the time needed to restore the data will decrease in the same relation.