Assertion failed when using high Q1 and Q2

["Rodrigo A B Freire" <zazgyn@xxxxxxxxxxxx>]

   List,

   I've set on my cache_dir directive higher values for Q1 and Q1, I say, 
Q1=100 Q2=160.

   After this setting going on production, the cache died:

2005/10/31 12:09:47| assertion failed: diskd/store_dir_diskd.c:1930: "buf"

   Is there any threshold on Q1 and Q2, for buffer size?