Help with expiry and item life times

[Stephen Woodbridge]

Hi all,

I just started using memcached with applications accessing it via the 
Perl API. We really like it!

I was reading the archive and there is nothing in the docs that I have 
found the explains expiry and item life times.

1) if I don't set and expiry for an item under what conditions, if any 
will if get removed from the cache other than an explicit delete operation

2) we set an expiry of 7 days for all items, but are running out of 
cache space, is there away to expire cached items early, like everything 
that is greater than 5 days old

3) is there a way to configure the memcached to automatically expire the 
oldest items or least used items to free space for newer items?

4) items sizes, the bulk of the items in out file cache that is getting 
replaced are in the 500-1000 byte size (~90% count-wise) using about 75% 
of the space and we have 5K-20K items (~9% count-wise) with say about 
~1% in the 100-200K size. Are there any issues or concerns I need to be 
aware of regarding these?

Thanks,
   -Steve