Why aren't my Postgres WAL segments (up to the point of turning on archiving) being archived? The pg_xlog directory for my master cluster looks like this:

-rw------- 1 postgres postgres  16M Jun 21 21:42 000000010000000000000001
-rw------- 1 postgres postgres  16M Jun 21 22:42 000000010000000000000002
-rw------- 1 postgres postgres  16M Jun 21 23:42 000000010000000000000003
-rw------- 1 postgres postgres  16M Jun 22 00:42 000000010000000000000004
-rw------- 1 postgres postgres  16M Jun 22 01:42 000000010000000000000005
-rw------- 1 postgres postgres  16M Jun 22 01:49 000000010000000000000006
-rw------- 1 postgres postgres  16M Jun 22 01:55 000000010000000000000007
-rw------- 1 postgres postgres  16M Jun 22 02:05 000000010000000000000008
-rw------- 1 postgres postgres  16M Jun 22 02:30 000000010000000000000009
-rw------- 1 postgres postgres  16M Jun 22 02:50 00000001000000000000000A


The pg_xlog/archive_status directory looks like this:

-rw------- 1 postgres postgres 0 Jun 22 01:49 000000010000000000000006.done
-rw------- 1 postgres postgres 0 Jun 22 01:55 000000010000000000000007.done
-rw------- 1 postgres postgres 0 Jun 22 02:05 000000010000000000000008.done
-rw------- 1 postgres postgres 0 Jun 22 02:30 000000010000000000000009.done


When I first turned on archiving 006 was the current segment, but why weren't 001-005 archived anyway? Last time I set up archiving on an existing cluster (which was yesterday - I've been experimenting), all log segments were archived when I turned archiving on, despite the pg_xlog directory containing more than 50 previous log segments.

Relevant settings:

wal_level = hot_standby
archive_mode = on
wal_keep_segments = 2048  # I know, right :)
archive_timeout = 3600
archive_command = 'rsync -aq --delay-updates --ignore-existing %p postgres@db-slave:/mnt/pgsql/'


Note: I did change all of these settings (including was_level, which was minimal previously) when I turned on archiving earlier. Could it be that my wal level wasn't sufficient to warrant archiving, or because there is a mismatch between the prior level and the current level?
This is most likely due to the fact that at least the 5th WAL segment was used for recovery to get the database into a consistent state after an immediate stop. I'm not sure why the WAL segments wouldn't still be useful (e.g., for point in time recovery).