Let me share a trick I've used on every system I've been on since MPE V (it
works with MPEX or RESTORE).  Old timers probably know this already, but
this may be new for some:

I create a new device class called NOT1 on the system in SYSGEN for every
disc LDEV but 1 then START NORECOVERY.  (My memory is hazy on MPE V but I
think it is SYSDUMP followed by a Cold Load).

In VOLUTIL I also create the same Class Name called NOT1 (again for every
disc LDEV but 1) using the NEWCLASS command e.g.:

volutil:NEWCLASS MPEXL_SYSTEM_VOLUME_SET:NOT1
VOLUMES=MEMBER2,MEMBER3,MEMBER4,...

(I don't think the above is necessary on MPE V).

Now that I have this all set up I can either do an ALTFILE in MPEX, or do a
RESTORE to Device Class "NOT1" e.g.:

%ALTFILE <your fileset>;DEV="NOT1";LOCAL;DELACD;KEEPAMDATES

or

:FILE T;DEV=TAPE
:RESTORE *T;<your fileset>;DEV=NOT1;OLDDATE

Commonly, the %ALTFILE command will let you move a file to a specific disc
LDEV or a Device Class.  However, most default configurations on turnkey
systems just provide the two disc classes of DISC and SPOOL, and this
includes LDEV 1.  If faced with this configuration, and I wanted to move a
large file or (a bunch of files) off LDEV 1, I have to specify which disc
(by LDEV).  Meaning I'd have to stop manually and pick another LDEV when it
fills up.  This trick allows me to "not care" which disc they are being
moved to, save for the fact that I DON'T want them on LDEV 1, and now the
O/S will make those decisions for me.

I wrote this for the traditional MPE fileset only.  Perhaps someone can
expand upon this for POSIX files, if appropriate.