no space left on device

I'm running Postgres 7.1.3, and just started having a problem where my
dynamic site is going down (read-only DB, with no writes happening to the
DB) regularly (every other day). I have no idea whay this is happening,
and my search of the FAQ's and mail list don't bring up anything. i've
attached the error from the log file, at the end of this message.

Here's an output of the disk usage from within the DB dir

[postgres - DB]$ du -k .
1716 ./base/1
1716 ./base/16555
5192 ./base/56048
8628 ./base
116 ./global
32812 ./pg_xlog
11380 ./pg_clog
53192 .

Note that the pg_xlog dir is huge! Here's its contents:

[postgres - DB/pg_xlog]$ ls -al
total 32816
drwx------ 2 postgres admin 4096 Mar 29 2003 .
drwx------ 6 postgres admin 4096 Jan 9 15:04 ..
-rwx------ 1 postgres admin 16777216 Jan 9 15:09 0000000000000001
-rwx------ 1 postgres admin 16777216 Mar 29 2003 0000000000000002

What are these files, and what can I do to resolve this issue?

Thx,

Zeb

--
DEBUG: statistics collector process (pid 2523) exited with exit code 1
PGSTAT: Error closing temp stats file
PGSTAT: /usr/local/G101/App/DB/./global/pgstat.tmp.7823: No space left on
device
PGSTAT: AbDEBUG: statistics collector process (pid 2979) exited with exit
code
1
FATAL 2: write of clog file 43, offset 188416 failed: No space left on
device
DEBUG: server process (pid 3741) exited with exit code 2
DEBUG: terminating any other active server processes
NOTICE: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend
died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am
going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
NOTICE: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend
died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am
going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
NOTICE: Message from PostgreSQL backend:
The Postmaster has informed me that some other backend
died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am
going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
DEBUG: all server processes terminated; reinitializing shared memory and
semaph
ores
DEBUG: database system was interrupted at 2004-01-09 05:22:52 EST
DEBUG: checkpoint record is at 0/138CFD4
DEBUG: redo record is at 0/138CFD4; undo record is at 0/0; shutdown FALSE
DEBUG: next transaction id: 45811837; next oid: 65205
DEBUG: database system was not properly shut down; automatic recovery in
progre
ss
DEBUG: redo starts at 0/138D014
FATAL 2: write of clog file 43, offset 188416 failed: No space left on
device
DEBUG: startup process (pid 3785) exited with exit code 2
DEBUG: aborting startup due to startup process failure