Large and Growing Group of Files

Can anybody tell what these files are and what they do, and more importantly
if they are needed?

This database has been in use since about 2012 on PostgreSQL 9.2 and is
quite active. (both read and insert/change). There seems to be one group
of these files a week, total 316 files as of today. I have truncated the
list because all the names are just 5 digit numbers, with every so often a
_fsm or _vm extension. They are all in a subdirectory called
PG_9.2_201204301/16385.

----------------------------------------
[root(at)prod03 usr]# ls -al /usr/pgsql_tablespaces/PG_9.2_201204301/16385 |
wc -l
316
----------------------------------------

...... tail end of list.....
-rw------- 1 postgres postgres 16384 Feb 28 19:07 16479
-rw------- 1 postgres postgres 90112 Mar 13 14:11 16480
-rw------- 1 postgres postgres 114688 Mar 13 18:27 16481
-rw------- 1 postgres postgres 98304 Mar 13 14:11 16482
-rw------- 1 postgres postgres 81920 Mar 13 14:11 16483
-rw------- 1 postgres postgres 90112 Mar 13 14:11 16484
-rw------- 1 postgres postgres 32768 Jun 10 2016 16485
-rw------- 1 postgres postgres 57344 Sep 22 2015 16486
-rw------- 1 postgres postgres 8192 Feb 24 17:00 16527
-rw------- 1 postgres postgres 16384 Feb 26 17:36 16529
-rw------- 1 postgres postgres 24576 Apr 4 2016 16529_fsm
-rw------- 1 postgres postgres 8192 Dec 29 2013 16529_vm
-rw------- 1 postgres postgres 16384 Feb 24 17:00 16533
-rw------- 1 postgres postgres 512 Jan 6 2013 pg_filenode.map
-rw------- 1 postgres postgres 111220 Jan 17 19:33 pg_internal.init
-rw------- 1 postgres postgres 4 Jan 6 2013 PG_VERSION

----------------------------------------

I have never looked in depth at the database files before; just did it now
because I'm working on building a new server!

Regards,

John
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