Weird postgres errors

pgfail.log

In my Django error messages...

 File "/apps/projects/lib/django/db/models/sql/query.py", line 2347, in execute_sql
   cursor.execute(sql, params)

OperationalError: could not write block 341 of temporary file: No space left on device
HINT:  Perhaps out of disk space?

...

 File "/apps/projects/lib/django/db/models/sql/query.py", line 2347, in execute_sql
   cursor.execute(sql, params)

OperationalError: could not write block 1 of temporary file: No space left on device
HINT:  Perhaps out of disk space?

...

 File "/apps/projects/lib/django/db/models/sql/query.py", line 2347, in execute_sql
   cursor.execute(sql, params)

OperationalError: could not write to hash-join temporary file: No space left on device

...

In my pgstartup.log...

LOG:  logger shutting down
FATAL:  could not create semaphores: No space left on device
DETAIL:  Failed system call was semget(5432128, 17, 03600).
HINT:  This error does *not* mean that you have run out of disk space.
        It occurs when either the system limit for the maximum number of semaphore sets (SEMMNI), or the system wide maximum number of semaphores (SEMMNS), would be exceeded.  You need to raise the respective kernel parameter.  Alternatively, reduce PostgreSQL's consumption of semaphores by reducing its max_connections parameter (currently 2400).
        The PostgreSQL documentation contains more information about configuring your system for PostgreSQL.
FATAL:  could not create semaphores: No space left on device
DETAIL:  Failed system call was semget(5432128, 17, 03600).
HINT:  This error does *not* mean that you have run out of disk space.
        It occurs when either the system limit for the maximum number of semaphore sets (SEMMNI), or the system wide maximum number of semaphores (SEMMNS), would be exceeded.  You need to raise the respective kernel parameter.  Alternatively, reduce PostgreSQL's consumption of semaphores by reducing its max_connections parameter (currently 2400).
        The PostgreSQL documentation contains more information about configuring your system for PostgreSQL.
LOG:  logger shutting down

Stuff I've found online...

http://web.archiveorange.com/archive/v/9FNVlpq1Spe1pxNhzzXD
http://archives.postgresql.org/pgsql-sql/2006-09/msg00142.php
http://grokbase.com/t/postgresql.org/pgsql-general/2009/04/database-corruption/0945zmmgvqpnud7x5du4o43c72ce

On the file system ...

$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda3             29G   23G  4.8G  83% /
/dev/xvda1             99M   13M   82M  14% /boot
tmpfs                 2.0G     0  2.0G   0% /dev/shm