Details about pg_stat_bgwriter

Hi,

I'm trying to understand the information shown in pg_stat_bgwriter.

If I want to identify a possible bottleneck with the bgwriter, for what kind of numbers do I need to watch out?

Are the following values OK, or do they indicate that I need to tune my configuration?

checkpoints_timed : 6099
checkpoints_req : 291
buffers_checkpoint : 2767641
buffers_clean : 4522
maxwritten_clean : 1
buffers_backend : 609933
buffers_alloc : 1411947

I have read Greg's description (http://www.westnet.com/~gsmith/content/postgresql/chkp-bgw-83.htm) but to be honest I don't understand the explanation. He mentions a "LRU background writer", but I'm not sure to which column that relates.

Thanks in advance.
Thomas